Just recently, she can go for several hours without needing the loo, but it's taken quite a while for me to realise that. My dh is retired so home all day, but if puppy goes out for a wee/poo about 6.30 pm, I know I won't have to take her outside until about 9 ish. I still go and stand outside with her, so I know she actually goes. We've always done this and it works for us.
She is in her crate from 10 ish (no later than 10.30) until 6 am. We only get up at 6 because that's our timings, not hers. At the weekend I leave her until 7 or even 7.30 am. She hasn't messed in her crate for months now, although often did a poo in there in the early days.
I know lots of people on here will say to get up in the night and take her out, but I didn't. I'm too old and tired, as you say it was just like having a new born baby in the house! She didn't even cry/bark at night when she'd messed, I just came down to find it in the morning, only twice have I had to wash her because it was so messy.
She did cry at night for the first 5 nights, on and off, but I left her. I read lots before we got her and talked to lots of friends with dogs and realised it's just like babies, there is so much conflicting advice, you have to do what works for you and your family.
She has never gone in her crate much during the day, and can reliably be left in the kitchen/dining room with her bed, toys etc. when we go out.
A colleague at school got a puppy in Feb half term and he is happy to be left in his crate during the day, she goes home at lunch time to let him out and have a quick play. She does have 2 adult dogs though, so the puppy has company.