We tried out a new way of getting rid of stuff this weekend: Team Decluttering.
Get two people together. Lay down some ground rules, like no personal attacks or mean-spirited comments. You're decluttering stuff, not each other. As you go through stuff, switch off acting as a questioner: "Why do you want to keep that? When was the last time you used it? Can we just rent one when needed?" Be aggressive, but be nice. Sometimes the decluttering person will want to get rid of something the questioner wants to keep; then you switch roles, basically.
Some people find it easier to be the questioner, some people prefer to be the declutterer. Others like both roles. Switch them back and forth.
We filled six grocery bags with stuff to give away in a few hours doing this. And we're hardly at the stage of decluttering where that's routine. The best part is that it's a shared activity, rather than a solitary thing.