We got our first puppy, a black lab, 2.5 years ago.
I'd echo much of what's been said above - training is hard work & must be from day one, but it's worth it. Crates are a very good idea.
Due to my mother becoming very ill just after we got Elsie, we did end up leaving her for longer than was ideal early on, but it really could not be helped. As a consequence, we ended up with some of the kitchen furniture getting chewed, but she's well past that and we now have a very well behaved and chilled out dog that doesn't jump up at people (hate that) and does us proud when people visit and when we're out & about.
We bought a couple of stair gates. One to keep her in the kitchen when we go out & another to stop her going upstairs. She only ever goes upstairs (reluctantly) to have a bath.
My wife's family have had quite a few Spaniels and at the risk of generalising, they can be a bit excitable. Labs are great, there are several reasons for their popularity, but they do shed fur and need quite a bit of exercise.