it's always good practice to:
i) leave a few centimeters of extra length; if its end point had been loose/softer, right now? All you'd need is your cutter, shave off said extra few cms and you'd be good to go again
If on the contrary you've cut it just so, you'd have had to replace it altogether now.
(and barring circumstances that shouldn't be occuring [excess in-case temperatures, coolant constantly on very high temps, etc.], that's pretty much your one and only wear and tear point)
ii) buy more tubing prior to setting your rig up and count the length of each cut piece, which you then write down; that way you know both your total and your individual pieces' lengths.
(if you don't change chassis every time you change componenents, this is a time and trouble saver)
iii) have extra tubing in advance and/or don't be stingy where you shouldn't; if, hypothetically speaking, you bent close to swap that GPU you mention, swapped its tubing too yeah? And with the new one in, you noticed a change in coloration? Between old and new tubing? Replace the rest of it; all of it. Day(s) of waiting for its being shipped, vs having that surplus in your back yard storage.
(and if storing it, which again, you should, keep it somewhere cool, definitely no direct sun exposure; doesn't go bad with time if stored rightly)