Strangely enough, I don't. I check my alignment probably once a month and everyting has always been in order. I have a Besseler 23C with a condenser head (soon to be cold light head as soon as it gets delivered). It's pretty rugged and nothing ever changes without a lot of effort having to be put forth. I've really only had to align it twice. Once when i first got it, and last week when I replaced the plastic cogs that raise and lower the head.
For those who have temporary sports that they set up each session. How do you deal with enlarger alignment?