Is it necessary to clean every record?

Why have a VPI if you're not going to clean each new disc. I spend 2-3 minutes per disc for a thorough wash and rinse with that machine.

Yes, it is.

Only if you're obsessive compulsive. I clean records that appear or sound dirty. It doesn't always help, but at least I give it a try. With brand new records, I don't usually clean them before listening(I know, burn me at the stake). If I don't like them, I'm not going to keep them and it seems a waste to spend time cleaning them until I'm sure. By the way, I use a Nitty Gritty 1.5FI and it takes me a minute and a half max to clean both sides of an LP.

Not only every record but everytime it's played. At least in my experience this gives the best long term results. any dirt, even surface dirt, can be ground in by the needle. If the record is cleaned befor play this reduces the possibility of this. To me, it's less of a sonic benefit than a long term, record lasting benefit (as records are expensive and sometimes difficult to replace). Some people use a carbon fiber brush for the "in between" deep cleanings. This dry method gets rid of most of the loose dirt, but I still prefer using the machine to clean each time--I guess it is obsessive compulsive at that point.

What I do with used records is to clean them with my Nitty Gritty, then treat them with Gruv Glide and place them in a new poly lined sleeve. I wipe the jacket with a slightly dampened cloth and, after drying, store in a "japanese" resealable cover. I put a "GG" on the cover with a magic marker. This way I know an album is clean and the need to reclean is minimized by using a new sleeve and cover. The cover also protects the jacket from deterioration. I usually do the same with new vinyl.