Does using alot of HDD space, reduce their lifespan?

No, the life expectancy of a hard drive is basically independent of how much data is on it. The same is not true of Solid State Discs, though, since a fuller SSD has less free space to use for wear leveling.

I disagree.

With fragmentation the read head must traverse a further distance. Larger volumes of data are more likely to be fragmented and thus cause more mechanical work to be done by the HDD. Increased work reduces lifespan.

Additionally by using more of the drive space i.e. more sectors you have a higher chance of bad sectors developing and increased reallocations occurring. This will absolutely cause the read head to do more work as it will have to go to the reallocation reserved area. Again more work and reduced lifespan.

However quangluu96 it's a bit pointless to consider all this. Just use the HDD the way you want to as you are far more likely to run out of space before the HDD fails!

THX ALOT