I don't believe a small to medium size operation can justify the inventory investment in reels of hose and a BUNCH of fittings( and probably still not the right one). Most of my farm machinery uses either 1/4, 3/8, or 1/2 inch hose.
I have invested in having a 6ft, 12ft, and 18ft hose made in each of the three diameters with female #8 jic ends on each hose. I then purchased about $100 in various adapters. So far, I've used these spare hoses at least
6 times (on a weekend while baling, mowing hay, or bush hogging) to keep me going until I had the time to get the proper replacement hose made up.
Twice, I did not have the proper adapter needed and as a result was "down" until Monday. It's really like having a spare belt for the round baler.
when ya working around rain, more so planting and harvesting times. and something breaks. you are in trouble more so in rainy years. and ya only get 4 to 8 days of working time in on the fields. a day or 2 of down time, can mean entire field not getting put in till late, or being harvested rather late.
but if ya have mission critical stuff. i would assume the farmer has some sort of spare hose much like what you have done. that or have direct contact numbers of service call folks, that will most likely have the stuff. and be able to make a drive out and do the repair work.
if a hose busts in the field. most likely you are stuck in the field. and unable to take it out onto the road and drive the implement back home or to a dealer. and most likely implement and tractor are left in that spot. or drove up to nearest area to road. to allow easier fix.
i would imagine, you would also need an assortment of tools. from screwdrivers, socket wrenches, box end wrenches, hammers, funnels, hydraulic fluid, PB blaster or like, and it comes down to, are you setup like a mechanic might be with tool boxes on the truck with other stuff. or is it easier to call a service person, that can look up specs quickly. and grab a couple parts off the shelves and make a single trip to the area and do what is needed vs multi trips and longer down time if done by yourself.
for me, having some spare radiator hose is worth while to have around with some adapters. i replaced some hyd hoses, (outer coating cracked away, starting to pinch, etc...) i save those hoses. they are still good. and usable in a pinch. and like you if i was bailing hay, and running implements that had long hyd lines, and multi hyd lines. i would most likely have a few different sized hoses with a small parts bins with adapters.
but to have 100's of feet of hydraulic hoses. and lots of adapters. just does not make since to me, exception perhaps is some sort of machinery plant, or like were many things in the buildings run off of hydraulic hoses. and if that is case, the mechanics most likely have crimpers, and buy by the reel of hyd hose. and have a good size bins with various adapters. or the tractor is an older tractor and all the hoses are to a point of needing to be replaced. and the person is buying in bulk, plus a crimper and enough fittings. to do a re-haul on a tractor and possibly some implements.
I did when I saw the seriousness of the thread as I continued to read then I came to this post 
