The phrase "Never wake a sleeping baby!" is probably one you've heard many times. I know when I first began embarking on a sleep schedule some older generations of my family were horrified that I would even consider waking my daughter.
It's true that when babies are first born, they need their sleep to recover from the birth, as do you. Let them sleep for the first few weeks as long as they like.
It is only when you're ready to start some kind of sleep schedule and help your baby consolidate their sleep it may be time to wake them up. There is no right or wrong age to start a sleep schedule, I'd recommend somewhere between 8-12 weeks but you can give it a go earlier if you wish but it's also never too late.
Babies aren't born with a circadian rhythm ready to go, they don't know the difference between night and day and it is our job to help them get there. There are some easy ways we can do this.
Wake them at the same time (or within 30 minutes of the same time) each day. If you want their day to run around 7-7 and one day they're asleep past 7.30, it may well be time to wake them to keep them on schedule.
Try to follow age-appropriate schedules and awake windows for their age (see my programmes for month by month examples).
Try to get lots of daylight in their awake times and keep sleep times dark or very dimly lit - the darker the better if this is possible.
When you first begin a schedule, you may simply have to wake babies up to help them get their body clock in order. Do this gently, I personally walk into my daughter's room, turn off the white noise and open her curtains. If she doesn't stir, I begin doing things such as putting laundry away and singing until she wakes up gently.
The phrase never wake a sleeping baby is just not going to help you maximise your night sleep - get waking if you need to.