Is Time Machine actually practical for anyone on HN? It seems as if for anyone who has a non-trivial amount of changing data on their laptop, Time Machine would be completely ineffective over a Wifi network (or even wired) - it would just be constantly transferring data and thrashing disks; on my desktop, I could barely afford even 1 complete backup, yet most of the data being backed up is cache files / stuff I don't care about losing.<p>Am I wrong on this? I've never actually tried to get it set up... does it deal with times where the file share isn't connected?