Cons:
You could mess up your events, ceremonies, birthdays. If you don't know when someone's birthdsy is, you might be in trouble, or your own
You slso won't be able too redo ceremonies, but you can redo events as much as ypu want. But when your a new player like me, you should keep that in mind
You could potentially go too far in the past and forget to bring some extra plutonium to get back. And no one knows when a bolt of lightening is going to strike and where.
In ACNH there aren't really any actual consequences for TTing. Weeds and roaches are slightly annoying but easily fixable. You can quickly profit off of turnips if you know what you're doing when you TT. You don't have to worry about villagers moving out or flowers wilting. The biggest consequence is ruining the immersion with seasons, events, etc., but once you've played the game for over a year it doesn't make that much of a difference since you've already seen everything by then.
I used to TT a toooon in ACNL, but I haven’t really done it in ACNH. I usually do it when I needed to make sure a villager was safely moved in. Lately, I’ve had to play at night so I’ll TT a few hours back to make it earlier in the day. I definitely don’t judge people for doing it, but I’ve just really liked taking things slowly. I usually have enough projects going on, anyway.
For me personally, primarily my experience wi try time traveling is:
Pro - I can schedule certain in game event and happenings (like island hopping or holiday events, etc) to accommodate my real life schedule
con- I always find that for me time travel makes the game feel a bit rushed and stressful.
so even though I get a bit impatient at times for certain things, I generally do not time travel except for situations where real life has to take priority, or if my impatience starts to bother me, though in that case I am never quite sure if it is worth it for me.
However, I really have no issue with anyone who does time travel, especially if it enhances the game for them. I think it is just a matter of different play styles.
Oh yeah because last year I remember someone on Twitter who went off on a rant saying "Time traveling is cheating" which really sparked a huge debate. Again there is nothing wrong with using time travel and like others say people play the way they want that is not harming them.
Pros-
You can have unwanted bridges and inclines removed faster.
The villagers won't move away (without warning) on you like it was in the past games.
You can put a villager who talked about moving (and you told them to leave) in boxes faster.
Get mail faster
Cons-
Can mess-up turnip prices
Turnips will rot faster if you go backwards.
Pros: You can play however long you want on your own time. This was a big deal for me when I played NL and was a busy high school and college student- I often didn't have time to sit down and play everyday, so instead I would enjoy playing in bursts on weekends and TT through the days that I missed during the week. This way I didn't miss out on events, birthdays, new shop items, etc.
For me there is no cons really. I don’t mind the roaches ( it’s sad when I accidentally kill them all). I don’t buy turnips , so I don’t worry about them spoiling. I also don’t mind weeds , plus I have no areas where weeds can freely spawn.
Pros: Everything
I can do events whenever I want.
I can buy more items from catalog.
I can play during whatever time of day I prefer ( usually from 2-5 pm).
I can get villagers instantly moved.
Pros: Getting ordered items fast, Relocating stuff moved faster, Villagers that I want to move ask faster.
Cons: Weed Growth
Since I'm pretty much someone who's used Time Travel since New Leaf I use it often usually to get items fast especially if it's excessive amounts I need like Simple Panels. There isn't many things that can go wrong in my opinion, minus weeds but it really isn't dangerous or anything and if it's considered cheating or not, it's not really something that matters to me since everyone should just play the way they want and that's all there is to it. I've never really considered it cheating though since it doesn't require any AR and isn't like putting trees in water or Star Fragment Trees, which is completely fine if you do want to do that but I guess that's why I've never seen it as cheating.
I don't TT because I like to take the game day by day. I don't care if someone TT, they can play the way they want to. There were defintely a lot more anti TT in NH then there were in any other game and I feel the pandemic bringing in new players soap-boxing 'the right way' is to blame.
There aren't as much people who go after people who choose not to TT because it's their preference, but they are still there. Both can jump in a river.
You have to deal with your residents asking you where you’ve been, are you mad at me, I’ve missed you, and so forth. not a big deal once you get used to it. At first it would make me feel bad. Of course, I am sensitive that way.
The biggest con of all with time traveling is that you get sick of the game faster imo, and once you start TTing it's incredibly hard if not impossible to stop. Not that I'm against it or anything, as I TT myself. Just based on my own experience - it can ruin the game a little imo.
The biggest pro is definitely getting things moved around/receiving more items faster.
In the end it's a matter of personal preferences. I never TTed before NH which looking back at when I was a child with Wild World it would've been better than being sad because I had been busy one day and had missed the events. Now with NH I started TTing and it was pretty fun, I decided to contribute in some way with my experiments and test all the methods for village hunting that were being discovered the first months. I have a reset problem anyways as I love to reset my games and replay them, even AC games when I happen to not play them for a long time. So after I was done and had the opportunity to gift some dreamies to my friends too and to lucky people here/ Nookazon (my friends wanted Raymond, Judy... all the new ones that I don't know right now but at first the prices were a little too much and scammers where a big issue), I decided to drop it for a bit since the updates weren't really calling me back to the game (+ life got real busy).
Now I re-started again but on September last year, that it was when I left it the last time more of less, and I do small jumps to reach today's date. Not playing day by day, maybe 2-3 day jumps or so. I got to see the events I hadn't seen yet at least, and to be honest I'm being lucky with my villager hunt. But I'm trying to not stress out about villagers and completing stuff. Pros on the other hand, well, you are in control of the pacing of your own game, and if you're a fan of finding out how some stuff works like the campsite method you can experiment with it. Plus people that work until late night need to do it anyways, they have the right to play a game they bought. Or if you have a 24h shift on an event day... Everyone's case is different.
The only real con I see about TTing is the common errors when you're new at it (turnips, missing events, or getting so lost that you don't remember what was the last day and jump too much). But I advise to those who want to try it to do it slowly, don't burn yourself out, try to not feel like you're in some kind of racing game. And personally I've found better jumping a small amount of days than weeks or going day by day.
One thing I've never done though is travelling to the future or past to get items. Like just TTing for that, to get an item early for example. It will come eventually so why rush it? But I get it, when people have that itch to decorate who am I to stop them?
I like to play ac when it’s sunny and you can see everything, but I am mostly on at night time so I am constantly changing the time to be daytime to play. I also go ahead a couple days at a time and then get busy so I feel it all balances out