Currently Being ModeratedJun 5, 2012 5:01 AM (in response to peternevill)
The question to ask yourself is .... if you lost all the data on your MBA, would it cause any issues? If yes, then you should at least have an external hard drive that you periodically hook up to to backup your data. I like, and use, external hard drives from OWC as many of them use Oxford chipsets, which work well with macs. I use this one for a portable backup.
Currently Being ModeratedJun 5, 2012 5:41 AM (in response to peternevill)
Time Machine not only back up your data but also (which is more crucial to me) a state of your system. I have MBA mid-2011 and back up my system (Lion OS X) using Time Machine, since when something goes wrong with the system I don't want spend time on internet recovery from the ground but will use Time Machine to rather quiclky restore the previous system state with all its data.
Currently Being ModeratedJun 5, 2012 6:10 AM (in response to peternevill)
As Time Machine uses up precious GB on my lean MBA I wonder if I actually need TM?
Given the statement above, you must be thinking about TimeMachine's mobile snapshots. This is a 'smart' feature recognizing that your data comes first so as your need for hard drive space expands, the amount of space TimeMachine gives to the mobile backups decreases. It can also be turned off using the terminal command found here.
Whether you use TimeMachine or some other software/system to backup your computer isn't important - that you have a plan is. Right now you have no backup plan - you have a recipe for a multi-hour cursing session as you reinstall your operating system, reinstall all your software, configure your system so you can access your gmail, dropbox and iTunes account, and then download some music and your entire DropBox. Then the cursing will start anew over the next serveral days as you slowly discover all the things that you didn't have backed up and should have.