Basically once the razor starts to pull a lot, or doesnt remove hair, its time to send it to be honed!

This is a good reason to have two razors, then when one of them is out to be honed you have another one to keep shaving with.

Of course, you can get some hones and hone it yourself, but then you need to get more razors to make the hones worth the spend. But if you end up with too many razors, you need to get more hones and strops to keep them all in best condition. And then you need to get more soaps and brushes to use with all those razors... Arrgh, feel the AD's!!