We had a working line as our first dog and she's remarkably chilled.
Toilet training and crate training essential for us. Toilet training was only two weeks but it was winter and it felt like the longest two weeks ever.
I thought I was prepared (grew up with dogs) but it was much more unrelenting than I expected. I wasn't prepared to have puppy blues, which stayed for around 8 weeks.
We spent a lot of time training. Loose lead walking and recall from day one. Total Recall is a useful book.
Mistake we made: we over socialised her. That's one thing we'd do differently. Our lab's kryptonite is that she loves other dogs too much and it made recall training so much harder. She's 19 months now so it's easier to recall her away but the first year was horrendous. She was a frustrated greeter.
We didn't really have a chewing stage so we're lucky in that respect. Dog isn't really left alone as there's always someone around but can happily stay on her own for 5 hours (never tried longer).
Our dog doesn't like swimming though. She only likes to go in shallow water. Will retrieve if there's nothing else to do but lose interest if there are other dogs. She was the only dog in gun dog class not interested in retrieving. The trainer said this happens sometimes!
It's hard work at the start but she's super easy now at 19 months.
Perhaps the biggest change for us is that everything now revolves around the dog. We've lost spontaneity. Vacations are now mainly to places she can come with. Visiting family abroad costs us a fortune as we pay for home boarding which is expensive where we are.