As I have been using philips HR2985B for more than
Motors themselves do not really wear out in the electrical sense, more the brushes may need replacing, or the motors bearings may become worn, The commutator may also have to be cleaned and/or skimmed, Also the wires and connections may need replacing, but as long as a motor is functioning OK, then it doesn't really get "Weaker" with age. I have seen well maintained, 100 year old motors still going and strong doing the same task as good as the day they were made.
In saying that though, there is no real good reason why you couldn't replace it? As long as you can get, a similar Motor that's an exact physical "Fit" onto/into the existing Mounts etc. Then you should have no trouble, at all.
Another thing I guess you could take the existing motor to a motor re-conditioner, they will replace all the bearings, wiring, brushes, if any, rewind the armature, and fields, if any.. skim the commutator, whatever it takes to return that Motor to "Just Like New". or pretty close.