For some fishing, I change out spools depending on the conditions - mainly if whomever I'm fishing with has his own 12 wt or not. If he does, then I have two separate 12 weights set up.
Though it's nice to have quick change spools with the captive nut, it certainly is not necessary.
Since most of my fishing is done from a boat, there is almost zero chance to lose the draw bar nut, though I have an extra.
I change spools freqently enough that the little draw bar caps are in a shot glass in my cubboard. They are purely for show and irrelavent from a functional standpoint. In the picture below you can see the shiny spot in the middle of the drag knob. That's the end of the drawbar that I never put those little caps on.
That way I don't have to remove them when changing spools. So, since I don't have to mess with springs, end caps or any tool at all this is very nearly as fast as a quick change - taking maybe 20 seconds at most in tough conditions. All I do is spin the drag nut off, pull out the spool with draw bar intact within it, insert new spool (with drag bar already in it) and spinn the drag nut back on.
Though you cannot tell from the pictures, there is a glob of extra drag grease stuck to the inside of the reel frame.
The picture below shows the offset reel foot. This balances the reel perfectly so it hangs plumb under the rod handle. It also pushes the spool toward the wind side and makes it easier to level the line when retreiving backing and fly line.
As many have said, backup reels are important. And as a buddy of mine says, you could hammer most ported reels flat with a Tibor, and go right back to fishing.
My Tibor maintenance consists of a hose down, most days. Often even that doesn't get done since I like to sleep ocassionally. My Nautilus' reels get the same. Though I wouldn't intentionally submerge the Tibors, or set them in the sand (I set them in my hat on the beach), a quick dunking does not result in enough water intrusion into the space between solid spool and solid frame side that it gets into the drag gear bearing grease.
If I dropped the entire reel in salt water, I'd just pull off the spool and fill the frame with bottled water a couple times, sloshing it around to get rid of the salt. At some point after the end of tarpon season I'd clean out the thrust bearing and repack with new grease.
The reels to avoid for saltwater, especially, are those without the drag easily accessable without tools yet not totally waterproof. If you are comfortable with a ported frame, go for it. I prefer solid frames and solid frame-side spools with draw bar drags.