I will sometimes lightly squeeze pairs together or plink them. I'm looking more for just change from what they were before or for a really notable difference between them. Tension meters and stuff are for the wheel builders that know more about wheels than I do.
I will do it more often when I get a new wheel and less often as the get past the 300 mile mark. But probably once every 18 months or so I'll make a effort to check them all. Otherwise when I'm cleaning my bike I might grab a spoke or too randomly just to see.