I'll go with pretty much everything before 30. That was when everything really started to nosedive way more than before. Things were still kinda OK for a few years (inertia) but once the real health problems of getting older and so forth started to kick in, things started sucking much harder than before.
"Dusting is a good example of the futility of trying to put things right. As soon as you dust, the fact of your next dusting has already been established." - Carlin