I do all my own maintenance. Have done since I was 14. Apologies if that put any LBSes out of business because I didn’t pay them 20 quid plus parts for servicing, every 6 months.
I buy parts from the most convenient store.
For bikes that tends to be online.
For electronics kit that is more often than not a local store. €2 extra per order but I can order at lunchtime, and 99 times out of 100, it’ll be ready for collection on the way home, at one of two stores, and saves me the effort of a trip to the post office to collect 4 days after ordering.
If my LBS can provide the same service as my local electronics store, maybe I’ll use them more.
edit: apologies for my contribution to the thread drift, but all the major/popular German stores, and the French one, are all listed above.
edit #2: and the only guilt I have is ordering from Wiggle, which tends to be left at a parcel shop, which just happens to be my closest LBS