Sgt_Kickaxe - 12:45 am on Dec 14, 2012 (gmt 0)
You should run a couple of tests after every change. One full stop or bracket out of place can bring a whole site down.
Or worse, leave it up sending all the wrong header codes but *looking* normal.
More than a couple of tests too, if your htaccess file redirects from non-www to www that's one test, if it removes index.php that's another test, then a third test to reverse order and see what happens, then a 4th, 5th and 6th test to check that non-existant pages also behave as expected. Is your host sending soft 404's on some errors? a few more gray hairs on those, err, I mean tests.
In the end it's worth it, a solid htaccess file is like tylenol to your search headaches. Get your server logs ready, a cup of strong coffee, a second computer with different browser helps, a user agent switcher... don't forget about your mobile version of the site. Are you having fun yet? :)
I was just wondering, is there software out there that can do all of the testing related to htaccess changes besides log analyzers?