I am sure you are right and I have become slapdash. I have never noticed any problems with the fix however and it seems to last a long time. Is there a good B&W darkroom book to learn about advanced printing? I have an ancient one by Michael Langford, which has lots of colour stuff, as well as incredibly convoluted tips to produce wacky effects, which Photoshop will give you in a couple of key strokes these days.
Also, I use a Durst 605 colour enlarger. The negative holder is sandwiched beteen glass, which sometimes I feel is especially designed to trap dust. Would you advise taking the glass out?