Vinyl Sleeves and Jackets

Yes, always - for everything it gets an ultrasonic clean and then a new MSFL inner and a Sleeve City 5.0 outer (https://www.sleevecityusa.com/ultimate-outer-5-0-record-sleeve-p/9390.htm) -- these are great quality and well priced outers

Leaving it in the original sleeve just re-exposes it to whatever clag or contaminants were already there, especially if it was a paper sleeve

I put the vinyl in a poly lined sleeve, then place the vinyl outside of and behind the cover with the outer sleeve and vinyl in a 3 mil poly sleeve.  This eliminates having to slide the record in and out of the outer sleeve and (my thoughts at least) should help prevent ring wear.

I like the look of the outer sleeves @folkfreak linked to, the ones I use can be a little snug with double albums.

The old guy who ran the shop with the most consistently fabulous sounding gear I ever came across (by far, not even close) made a big show when he pulled out a copy of Santana Abraxas of getting his fingers all over it. At one point he was holding it with thumb and fingers of one hand right on the vinyl like its a Frisbee and the fingers of his other hand across it like some guy checking out the paint on a car. 

The method in his madness is getting across to people that vinyl isn't nearly the Faberge Egg its made out to be. I've got records gonna sound like crap no matter if they are cleaned by physicists at Lawrence Livermore, others that sound fabulous despite being played scores of times over the decades. Likewise I've got records been in and out of paper sleeves dozens of times and quiet, and records in poly sleeves seldom played yet noisy.

Your anxiety may vary, as they say. Mine is pleasantly placid.