I have a love/hate relationship with my rotary blade sharpener. I have the first electric one that they put out and it’s very fiddly about getting the stones in just right and getting the blades aligned just so. But once you do that it does a good job. I also have one of the rulers that has the sharpener on the edge and I use that fairly frequently which also helps extend the life of my blades.
And, I have to confess to taking a dulled blade out of my cutter, turning it around and putting it back in, which works well enough to get through a project in a pinch.
I use needles until they start to sound dull, then they get tossed. I check them for straightness before use and f not perfectly straight they get tossed as well.
My vintage Kenmore came all set up and “ready to sew” with an amazingly bent (and threaded) needle. fortunately the person who had been sewing with it that way had the zigzag needle plate on the machine!
Rob