A seven year old disk drive? I would trust it to be useful for testing and for educational/training purposes. But given a choice between using old drives for my system and data and buying new ones, I would buy new ones. Of course, I'd then take the old ones apart and keep the magnets. Those little magnets are pretty darn strong!

A seven year old disk drive is likely to be approaching the end of its life. The probability of it developing read and write errors is much higher. The probability of it having problems with its electronics is much higher. Seven years of heat/cool and power on/off cycles will have taken their toll.

Find smartmontools somewhere and check the drives' status. You might be surprised at what you find.