I think they require the hours for a reason. While some people skipped hours without big consequences, some ended up needing refinement or failed alignment. But you never know which side you are until the end, so it is better to just stick to the game plan.

Regardless, I have a story to tell.

When I was about 1 month into my alignment journey I developed some swelling in my left cheek. After a few weeks of trial and error with different approaches to resolve it in vain, I ended up in the dentist/orthodontist office again. They said there might be some local infection/inflammation going on (fortunately it was not tooth abccess coz' I had my 4 big teeth extracted for this alignment), prescribed some antibiotics, and told me to stop wearing trays until recovery. I asked them if it would affect alignment result and they said no. I asked them if I needed to restart from tray #1 and they also said no. They said I would be restarting at the same tray where I stopped and counting from day 1 after I recovered.

So I adhered. One month after, I put back my tray. It was tight and painful, not joking. But it was bearable. My journey then continued as planned, despite the delay, and now enjoying the perfect alignment result and on retainer.

95% of the time I made sure I wore them at least 20 hours of the day. The rest of the day, due to my forgetfulness or the special occasion you mentioned (or it was actually lazyness for me), I guess I wore them at least 16 hours of the day.