I get way too anxious and tend to check on my cuttings before I should. I have found that you need to leave them covered for a minimum of 4 wks. After that, you can check them any time, but always make sure to mist the stems and remove any dead or moldy leaves. If any stems look black at the base, remove them too. Be sure to tamp the soil around the stems so they are secure. By 8 wks, you should be able to tell if they've rooted or not. They should be tight in the soil. If they're wiggly, they aren't rooted, or only partially rooted. Tamp the soil around the stems again if they are loose. Once you are sure they've rooted, uncover them and continue to mist them a couple times a day. They have to get hardened off. That takes a few days. I lost a lot of them opening them up too early and not keeping them misted. If they're well rooted they will do just fine.
And just a tip... John Bagnasco from Garden America radio show told me to use Hormex #8 rooting hormone mixed 50/50 with cinnamon. The cinnamon apparently helps to stop rot. Not completely, but it has really helped. I'm now able to root florist roses, which have been extremely difficult to root before.
It's so much fun and so rewarding when you loosen the soil and see all those nice little roots! Good luck!
