As you can see from my AddonList, I use a lot of addons. Keeping them up-to-date, especially on patch day, can be hard.

Also, since many of my addons are from WowAce and one of the things the WowAce community does is break problems up into smaller pieces, you can easily end up with dozens (or hundreds if you are like me) of addons you need to keep up to date. This can be really challenging without a tool.

Because of this I wrote WowAceUpdater (WAU) which you can use to easily update your mods before going into the game. Since writing WAU a number of other updaters have come online, some for other sites and some that work with multiple sites. More recently, I also wrote a very simple command-line updater for Windows PowerShell that works with many addon sites.

Links:

• WowAceUpdater - Windows only. Requires .NET 2.0 runtime
• PowerShellAddonUpdater - Requires Windows and Windows PowerShell.
• World of Warcraft UI Updater - aka WUU. Works w/ many addon sites. Cross platform Python.

There are others out there, so if none of these work for you, take a look around.