Back to OP’s question - I just paid £144 for labour for two people for and hour to look at my wind instruments and fix a problem. I think if they had had to remove old transducers and wire and replace then I would have expected 3 times that for labour.
I think a ot of that will come down to the type of sailing you day and availability of alternative supplies. If you carry a spare that will be big enough to last you for your longest likely trip then it's irrelevant - which one is cheaper would be my steer.
However - if you're away from home...
I have a rechargeable SUP Pump. No idea how many dinghies i could inflate with it on one charge but plenty of juice in it. Expensive £120 but good. Previously we had a coleman that was high volume, low pressure and would get it most of the way there and then use the manual pump but when it died...
Have only l;ost one fender and that was where it chafed through on the toe rail - My clove hitches ( and even those of my daughter) have not come undone - That said - 3 strand rope and with a reasonable tail may help.
We chartered once in Greece a few year ago and the lanyards on the fenders...
I would disagree wholeheartedly. A lot of manufacturers put regular material online showing how to use their kit, many places have pilotage guides and of course there is a boatload (sorry) of material of varying quality where one may need to be selective in choosing what lesson to learn where...