As a sensor cleaning challenged individual (have made things worse myself twice trying the DIY method), my outlook on dust has evolved using Leicas.
Have rarely ever had dust issues with my Olympus mirrorless bodies, but my M9's seem to always have 2-3 spots even just back from Leica cleaning service, but compared to dust spotting scanned 35mm frames captured with the M4 or M6? I'll deal with the 5-7 seconds it takes to fix if there's a couple of spots in the skies of an M9 file. Keeping the aperture set to f4 or wider also helps.