I bought cupboard locks but never used them, and didn't actually find we needed them tbh. I had (and still have) a gate at the door of our living room because all DH's bikes (yes, he has a few
) and cycling stuff is kept under the stairs so for us that area was the most dangerous to a crawling/standing baby, so we'd often have that shut so he couldn't access any other part of the house. If he was anywhere else (kitchen etc) then we would be with him. Having said that though, he wasn't the type to be into something the second you turned your back - if you left him for longer then yes, but it took him a while to think of the mischief
If a tube of cream was left in reach though, or a pen, that was a different matter
We also have socket covers, might consider removing these after reading Amanda's post though
TBH there are very few sockets that he could get to in our house, and he's never paid much attention to them anyway.
We also had a gate at the kitchen door, and at the top of the stairs. I basically baby proofed the one room (our living room) and put a gate at that door so that he could be left in there, safe, if I needed to do something. I still do that now. I didn't need to babyproof that too much either - just removed any photo frames or ornaments that were in reach etc.