We're glad you asked! Most of our print books check out for four weeks at a time; you can renew them five times if you need them longer. After that, we just ask that you bring them back so we can see that your dog didn't eat them. If you want, you can check them out again and start the process all over again.
Reserve books -- which include textbooks and others items being actively used in CWI courses -- are more limited. Many don't check out at all, while others check out for anywhere between a couple hours and a couple weeks.
If you want to check out an ebook, you can usually choose how long you'd like to check it out (up to a month). After that date the file will expire and you can check it out again if you want.