Get My Mojo Woikin'

Most instruments have what their players will variously describe as "mojo," "history," "stories to tell," "personality," et cetera.
The older an instrument is the greater its history is assumed to be. Surely a violin that is four hundred years old and worth (this I think is a great part of the catch) millions has to have better tone than a brand new violin produced at the same shop. It just makes sense?
It never has to me. There may, in fact, be building techniques they previously employed or materials used that are the reason for the tone and so we see why some pieces might be sought after.

But to this day, much if not most of it is speculation or the will to believe in something magic.
Why would a guitar once owned by Jimi Hendrix make MY playing any better? It's silly to think that way, no?
Musicians would, for the most part, disagree. They believe in magic when it comes to their instrument and the effect it has on their playing.

It started when collectors in the 1980s began buying old Les Pauls at ridiculous prices. All of a sudden, classic Gibson was worth ten twenty, one hundred times the original price. And at that point, players felt the mojo risin'.

I have six guitars, the oldest is an incredibly cheap and yet wonderful nylon stringed classical guitar. It has no mojo (aside from a sticker that reads, "Are you stoned or stupid?"), it DOES have wonderful tone.
The rest are all 2007 or newer. Would having a 1962 Jag, worth $4,000 make my playing sound better than the $800 Jag that it happens to be? Nah...

Part Duex - Relicing
The act of intentionally aging a guitar to make it appear older than it happens to be.

Rusted screws and hardware - worn paint. I've never had any of my guitar in that conditions and I do not baby them in any way. The gold plating wears off. The knobs show accumulated dirt. but for a guitar to look like this, someone had to employ sandpaper. No arm I've met sweats paint off. Oh, and Fender will charge you a premium for aged guitars. There are many techs out there that for a substantial fee, will soak your knobs in coffee grounds, use the above mentioned sandpaper and drop implements like screwdrivers onto your guitar in an effort to make the guitar appear as though it has stories to tell. We can delve into the world of fakes and counterfeit guitars another time.

There is one other effect aging has on finished wooden instruments that I have seen and witnessed, that I do enjoy.
It's referred to as, "checking."
When Mr. Gibson first began (the end of the 19th century), furniture was coated with nitrocellulose lacquers.
These lacquers do not react well to sudden changes in temperature. If a guitar which has been outside in the cold is then exposed to moderately warm room temperatures, as the wood expands, the finish cracks - checking.
Like the spiderweb cracks in old porcelain, the checking itself can be beautiful.

Part  Trois - Polyurethane/Polyester - Modern Finishes
Poly finishes are not supposed to check. They are plastic. (We can discuss whether a plastic finish strangles the tone another time),  What I would guess is Fender and others use a nitro undercoat - that will yellow with time and then finalize it with a poly overcoat.
The reason I would hazard this guess is I have been temperature cycling my MIM Jaguar. If poly doesn't relic, why am I doing this?

I lay the guitar outside in the hot sun for an hour and then bring the guitar into the cool, shaded house several times a day. The wood expands and then shrinks.
At night I am reversing the extreme, but still cycling. An hour out in the cold night air and then into the warm house.

Most relicing I have seen is produced horizontal to the body.

After just one day of a couple of cycles I began to see very fine cracks in the undercoat.
The guitar is smooth to the touch. And they run almost vertically. Northwest to Southeast if one were to hold the guitar up by the neck. If they get to the point where I can photograph them, I will.
Now, to spot the lines easily I have to look into the reflection of a light source - a line will be evident and the image will be distorted like a broken mirror.
As I am fond of saying - we'll see.

Strange daze, indeed.