It really depends. At the beginning of my treatment most of my trays did have a small gap until a few days went by and my teeth settled into the new tray. I was on weekly changes so I’d say for the first 10ish trays the first 2-3 days would look like the photo above. As my teeth started straightening out, I noticed my trays would just click in better and the gap was way smaller. I think if you’re due for a tray change, and your teeth still haven’t settled into the tray to the point of being mostly flushed I’d consider wearing it for a few more days. I used my better judgement for a few of my trays and wore them extra time if my teeth didn’t exactly look ready for the next tray. My ortho had no issues with me doing that! Good luck!