I’ve owned and used on and off a Gaggia Titanium for over 16 years now. It has not needed any maintenance for at least 10 years and over 5000 coffees (and about as many starts from cold).
I did have to replace its motherboard and fix some underbody rusting issues a few years back (due to a minor leak in the steam system), but that was after many years of service.
Unfortunately, this machine has long been discontinued and I don’t know if the current crop of Gaggia/Saeco/Philips BTC machines are as reliable (they have more plastic in them, which would have eliminated my rusting issue, but may have other points of weakness)