Sven.... firstly, congrats on hitting the 50K mark
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One great thing about the Bandit is there's just not much to do beyond regular maintenance. Aside from oil/filter changes, air filter changes, tires, chain/sprockets, spark plugs, brake pads and valve adjusts I wouldn't worry a whole bunch unless something breaks.
If you're really looking for stuff to do then I'd consider new fork oil, brake fluid & clutch fluid at the top of the list. Inspect your wheel bearings (front & rear - don't forget there's an extra set in the rear IIRC) and your swing arm bearings. Swing arm bearings will likely need repacking at a minimum depending on how much rain you ride in. Steering head bearings are good to check as well, however you'll usually notice if they're shot before they need replacing.
Grease/Lube all pivot points... levers, kickstand, centerstand, etc. If you haven't replace your brake/clutch lines I'd add to the list for a future mod. Other than that, watch for clutch slippage or cam chain noise (worn out tensioner) but don't worry or obsess over either one... they'll happen when they're ready.