Your peds are SPD's
Upgrade to the XT's or the XTR's, they both have sealed bearings.
Have the XT's on my commute bike and the XTR's on my nice bike.
XT'S are now 6 years old the XTR's are now 4 years old. Have never had to service, take apart etc
Well worth the money.
What about the M540's? Aren't they sealed bearings too?