This is really useful especially when you are wearing an oversized tshirt. When wearing an oversized shirt or T-shirt without ticking in gives a visual illusion of a short legs which isn’t really fashion cool. Tucking in gives a perfect illusion of a really long leg. This also defines your waist. If you don’t wanna tuck in, you can tie your shirts up stylisly the the front or side with a rubber, but just ensure the pockets and belt line of the Jean is showing.
If your jeans are too long, roll up! You can do this while wearing a fitted jean too. It shows your foot wear very well and also your ankle too which really elongated your legs too.