E90 family (about 2006–2011)
Six-cylinder engines in this era commonly develop oil leaks at the valve cover and oil filter housing gaskets, and use an electric water pump and thermostat that wear with age. Front control-arm bushings are a frequent suspension repair.
F30 family (about 2012–2019)
Many of these cars use the four-cylinder N20 engine in earlier years, where timing-chain guide wear has been widely reported; noise at cold start is the early sign. Oil-filter-housing and valve-cover leaks remain common.
G20 family (2019 onward)
Newer cars are mostly in routine Condition Based Service maintenance: oil, brakes with wear sensors, brake fluid, filters and battery registration when the battery is replaced.