Do you need to correct a spelling error on a large number of pages?

Are there terms you need to linkify across an entire subject?

Do you need to replace a category tag on 500 articles?

AutoWikiBrowser (AWB) can do that and more. It is a free-licensed, semi-automatic editor created and maintained by Wikipedians, available to editors who have made at least 500 responsible edits in the main namespace. AWB includes a powerful list maker (up to 25,000 articles), to help you gather the titles of the articles you wish to process. An extended AWB Listmaker is available as a plug-in. AWB will even do regex (regular expression) find/replace.