Just so that there isn't any misunderstanding, the fact that a hose is found collapsed when the engine cools doesn't necessarily mean the hose is bad.
If the return of coolant from the external reservoir to the radiator is indeed blocked, then as the engine cools something has to give to accommodate the reduced volume of coolant in the engine system; this will most likely (and preferably!) be one or more of the rubber hoses.
The issue of whether or not a hose needs be replaced is addressed by what happens when the rad cap is removed and also when the cooling system is under pressure. If the collapsed hose springs back out to its normal shape when the cap is removed, and it doesn't stretch out abnormally when the system is under pressure, then it might still be fine.
In any event, the root cause of the collapse is elsewhere, and that should be dealt with. Incorrect/ill-fitting/faulty rad cap, blocked reservoir hose, and accumulated gunk in the bottom of the reservoir are common.