How often to you clean vinyl and the needle?

Every record new or used goes thru my RCM, VPI HW17, before first play,  Then every record is treated with LAST.  Then every record gets a quick brush before each play on each side every time.  If any record gets noisy it goes thru the RCM again.  Stylus is lightly brushed with Stylast before each side is played.  I inspect the stylus regularly with a lighted magnifying glass several times per week.  If there is any sign of buildup (rare) I clean the stylus with an ultrasonic cleaner that I bought on Amazon that is made by Hudson.  It is remarkably effective.  Every six months the stylus is inspected using my Wild-Herrbrugg microscope.  This is mostly to monitor for wear.

I treat records with Last too, once. They even sound a touch better than without it.

I use an ultrasonic cleaner when I first receive an LP. Records are stored in proper anti static sleeves and album jacked is stored in proper sleeve as well. I never touch the surface of a Record with anything. Furutech anti static device. Common sense, IMHO, says never use anything that could push surface contaminants, visible or otherwise, into the grooves where the stylus rides. I clean the stylus every LP by touching it gently on a Audio-Technica AT617a Cartridge Stylus Cleaner.

Records in the Nitty Gritty when new. Rarely after that.  Stylus with Oznow after every side and usually a swipe with LP#9.  I have never had an issue with Lp#9 ever damaging a stylus or cartridge. 

I wonder how many of us who rarely clean their styli ever look at the stylus under high magnification after long term use. If you did you’d be motivated to clean the stylus every few sides. I routinely use Magic Eraser but to be really thorough I use a liquid solution and a tiny brush .