I have had my Time Machine backups going to an external drive hooked up to my Airport Extreme for as long as I can remember. This used to cause me all sorts of problems, but I very rarely have issues now. Part of that might be due to using a more defined backup schedule with [TimeMachineEditor](http://timesoftware.free.fr/timemachineeditor/),[^fn1] and part of that is probably improvements in newer version of Mac OS X. Still, next time I do get one of those
“*Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you”* errors, I am going to give [Garth Gillespie’s trick](http://www.garth.org/archives/2011,08,27,169,fix-time-machine-sparsebundle-nas-based-backup-errors.html) a shot.
[^fn1]: I backup overnight instead of continually through the day. Obviously this means that I have a bigger gap in between backups than the people who backup every twenty minutes.