On my main slide, I typically put powder on my seals once a year and I put dry lube on the rack teeth twice a year. On my bedroom slide and since it is a cable drive unit, I check the tautness of the cables quite often. If I find one that is a little slack, I'll tighten it up.
Other than that, I don't do much of anything else except to make sure there's no debris under the awnings before I close the slides. I do have a problem at home with a sparrow who insists on building her nest in the awning cover. I'll pull it out and the next week it's right back there again. I won't have that problem any longer as last winter I built an rv garage.
Ron