While some dealers may upsell service work (not all of them, but it does happen), I don't think that this is any more common with BMW dealers than any other dealers.

Things the dealer suggests may be considered upselling or may actually be valuable information that can save you money in the long run. You need to decide. If the items they suggest doing are covered under the warranty (which only covers defects in materials and workmanship, not wear) then fine, they will do them under the warranty.

If they are finding wear items (which you will have to pay for, not having the benefit of either full maintenance plan like the US or the scheduled oil change plan like Canada), just check back to the maintenance book to see if they are normally scheduled items. Use the BMW booklet as your guide. I had a dealer in the past (not BMW) which went to the trouble of printing duplicate service books and including them with the owner's manual. Those books looked like the factory maintenance guides but had much-shortened maintenance intervals

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue