This is my guitar:
I bought it in 1974. If memory serves, it cost in the vicinity of $300. So that conservatively comes out to at least 25 minutes of playing for each penny spent (figuring an hour a day playing on average). Reasonably well spent money.
This is my can of guitar polish:
I bought it in 1974. I don’t remember what I paid for it.
Yesterday I put new strings on the guitar and I took the opportunity to polish it up a bit. Judging by the feel of the can of polish, I think it must be close to half empty. So I only have a 35 year supply of guitar polish on hand.