I don't really have a set time. I haven't gotten mine cut in 2 or 3 years now. My sister cut my bangs at the very beginning of the pandemic, and may have trimmed my hair then too (can't remember), but before then it probably would have been at least like 6 months since I had gotten it cut. I just usually get it cut whenever I feel like it.
At the moment it's really long, over halfway down my back. I really like it this length because it looks nice and I can do stuff with it if I want. But it's also very annoying. It gets insanely hot, it's heavy, it gives me headaches sometimes, and it takes longer to wash/dry. I debated for a long time if I wanted to get it cut. I think I've finally decided that I'm going to, but I'm going to get it done at a nicer salon (I usually go to a place that is like $5 for a haircut lmao), so that I won't feel as bad about cutting it.