Definitely try to build up the time. Even though I am often home all day I try and find things to do that take me away from the house, could be as simple as going to the supermarket, running an errand etc. Where possible I do try to leave Harvey every day that we are home and it seems to be working, from what we can work out he seems to use the time to catch up on some sleep on the couch, occasionally I come home to something shredded but not often. We did use to crate Harvey until he learned to escape
which was when we found he liked to be on the couch where he can watch the world go by... We just use the same words each time and give him the same treat for consistency so he always knows we are coming back.