C.A.
My children are 12, 10 and 4 years old. The oldest two are boys and quit using pull-ups about a year ago. Their bodies simply weren't ready before that. We tried taking away the pullups but they would wake up drenched every night -- deep sleepers!
My 4 year old is not ready. She often wakes from naps with a wet bed. She has been day trained for quite some time, but her body is not ready for night time.
So, each child is different. And each parent is different. You do what works for you. The laid-back approach works for me. :)
Good luck!
Oh, and yes, we have had mattress covers since they were infants. :)