I guess my fall back pattern may well be the scout/SAK.
I started out with a scout knife dad gave me. Went in the army and carried the issue 'demo' knife for years. Bought a Buck stockman in the late 60's, and a Victorionx SAK. Then a few more SAK's. Even though I carried the Buck stockman for 25 years, there was always a SAK close by, and sometimes carried in tandem if I was heading off someplace. I went through a sodbuster phase in the late 90's, then my peanut stage until arthritis has killed that.
Now I have another stockman, but my old Wenger SI is still around. Since 1969, the Victorinox pioneer or Wenger SI has been a fall back. When I go on vacation, I send a SAK to myself where I'll be staying, and gift it off when I leave.
A SAK seems to be my lifelong fall back pocket knife. I know I can mail order one and it will be just the same as the last one. Or stop in any big box store and pick one up, and it will be fine.