My experience is muddled with divorce and a bunch of property changes, but the bottom line is my car insurance went up 74% with no driving related changes(read long term clean driving record.) The changes between the old and new premium were: divorced, no multi-vehicle, no auto-home, gender change, and change of address. It's a bit pointless to run scenarios to determine what caused each change, they happened, the computer spits out the new premium.
My premium is now close to average, instead of stellar cheap I had enjoyed for a long time.
Several discounts may be back in a few years with expected life changes.