I have always wondered this, but wasn't sure what would be better in the long run. It seems like extra sleep on the weekends would make me feel better, because getting up at 5:30 in the morning on the weekend (because I do on weekdays) doesn't really feel right. So I'm just wondering if I stick to my sleep schedule (which is 9:30 pm to 5:30 am), would that make me more tired or more rested on the weekdays?
According to the majority of sleep-related websites I found, you should go to bed and wake up every day at the same hour, including on weekends. This is because "being consistent reinforces your body's sleep-wake cycle and helps promote better sleep at night."
I would sleep in though if you had a lower average of hours slept during the week days, since the sleep you loose in one night may require more than just one single day to catch up. So imo go ahead and try to sleep in at weekends. If that doesn't harm your ability of falling asleep during the weekdays (you're not taking more than around 15minutes to do it), then it's all good.
That really depends on what you're aiming to do. You promote healthier sleep by sticking to your sleep schedule (provided that you get a consistent 7-8 hours per night), but sleeping in during the weekends also greatly improves your chances of lucid dreaming during that time. Either way, two days of sleeping in is not going to have a drastic impact on your sleep schedule as long as you don't go overboard and sleep the entire day.
Sticking to schedule.
The upside to not sticking your your schedule and sleeping in a few hours is that you'll most likely end up having a few extra dreams. I find that LD'ing is very easy if I wake up at my regular time, do a quick WBTB and then go back to sleep.
But yeah being consistent is the best thing you can do for your body, I'd rather give my mind some "candy" though, it's not like you'll be so out of balance that you will lose many hours of sleep in the long run.