We use this approach. 14 years in and have a mortgage as a shared expense (auto withdrawal from our personal accounts covers this). This has worked just fine for us.
Bigger purchases (car, new heating system) we discuss individually based on our savings and income at the time.
Same here, and pretty much the same as I've always done with partners.
One account for me, one account for them, and one shared account from which "shared" bills come from - be it rent or mortgage, electricity, food, etc.
Sometimes a person will say "I drove you to the countryside will you give me money?" or I'll say "I bought us tickets for a gig, you wanna pay me back, or you wanna buy me beer all night?" So sometimes there is some play back and forth about expenses/costs, but typically we transfer just enough to the shared account to cover the expected outgoings each month.
Bigger purchases (car, new heating system) we discuss individually based on our savings and income at the time.