External Hard drive size..... What size?

[Mikebike125]

I have a 500GB HD on my iMac. Is there any advantage to getting say a 750GB drive or should I just stick with 500GB. The reason I ask is since I would be using the external drive as the back up, I guess I shouldn't be putting anything on it exclusively because that would defeat the purpose of TM. Am I thinking correctly here??

I am new to apple and I have never had an external drive to back anything up before.

[Neil321]

BIGGER is always better in the harddrive world it just depends on what your backing up and how fat your wallet is

[killmoms]

Since Time Machine will keep both your current files and older copies of files that have changed, it might be wise to buy a drive larger than the one in your machine, even if the one you have isn't full. As it fills up, more space will be consumed on your external, plus the overhead for keeping older files.