Twice a year - Spring and Fall, I run my slide all the way out then crawl under and spray the tracks and gear mechanism with aerosol lithium grease. Then I spray the seals with slide out seal spray to keep them lubricated. Both products are available at Walmart.
I do the same as Jim. Very important to keep the seals lubricated. Do not use wd40 on them. Use the lubes made for the slide tracks and seals. As Jim said Wally worlds has them