Do you clean your records before play, after play, or once (and then never again)?

Budget option: I get remarkable results using London Jazz Collector's DIY cleaning solution and a 3D-printed home vacuum attachment I purchased off eBay: 

https://londonjazzcollector.wordpress.com/for-audiophiles/home-brew-cleaner-for-vacuum-rcms/

https://www.ebay.com/itm/291452416779

I clean new & used records on an as-needed basis. 

Add Blue Sticky Tack for stylus cleaning (every 5 or 6 spins), dryer sheets, and an anti-stat brush, and you'll have clean records for a song. 

I first used L'Art du Son on my Keith Monks. Then I used Walker 4 Steps enzymes and the Keith Monks fluid for re-clean from time to time. After that I tried AIVS and liked it better than Walker especially for a less "dry midrange".
now I have bought a KLAudio but kept the KM (because I 😍 this machine). 
Now all my record collection is washed first with enzymes and second with ultrasonic.
Recently I bought again a bottle of L'Art du Son for periodic re clean and find it is best sounding when I make a final clean with it. It is not expensive and if you let the fluid for 2 minutes on the record it cleans really well. And more than that it makes music sound really good to my ears.

@mapman 

I came across this ultrasonic cleaner, reviewed by Fremer on his web site,  Analogplanet. Even though I have a VPI 16.1, I am considering one of these in the future. I really like the advantage of being able to clean 12 records at a time. The price is considerably less then other ultrasonic on the market, and you can purchase options/attachments separately.

thats when I bought VPI-16.5, after reading this:
http://square-2.com/wp-content/uploads/Listener_2000sm.jpg
:-)

@bradf - you might look at Rushton’s thread here, which is based on an article he wrote for Positive Feedback. There is a relationship among size of bath, number and power of transducers, frequency, etc. viz surface area of records to be cleaned. (Sorry, I don’t remember the formula--it is buried in the long thread on DIY Audio about ultrasonic cleaning). @terry9 can speak to his experiments with the number of LPs in the bath v. cleaning effectiveness.
The bonus to DIY isn’t just cost-effectiveness either. You can take advantage of higher frequencies, heat control and other features that aren’t necessarily offered on the audiophile machines.