When doing any kind of alignment, always check the output of the tube. This tells you if your tube is resonating in TEM00 mode… This simply means the power is distributed across the beam correctly. Tube can go out of tem00 mode or they can just get less powerful. They can probably do both, but I’ve never seen it.
I cut these targets out of water color paper…
The only maintenance is keeping all the mechanical parts good and snug along with belts. If it doesn’t move, it’s likely not a problem.
I try to do it once a month, but it depends on how much you use it. I wipe down and lubricate all the bearing surfaces with white grease. Clean the optics, then do an alignment… once alignment is OK I go back and clean off the mirrors’ debris collected from the alignment exercise.
A check of the alignment is pretty fast, a couple minutes … a complete alignment on mine takes about 15 minutes from all loose mirrors.