Unfortunately, it's not quite that simple, as there are many different factors that come into play:

Firstly, skin, beards, beard growth and skin sensitivity vary greatly - and of course there are also differences in the Razor, the angle of the blade and how hard you press. Therefore, there is no one answer that necessarily applies to everyone.

Another thing is that it's actually grease, beard debris and dead skin cells that form a film on the blade and make it look dull in the first place.

If you want to, you can easily maintain the blade and get many (!) shaves from the same cheap DE blade.

Søren, one of our very experienced users, once did a test with control groups and everything. After use, he put the blade on a RazorPit - a silicone plate made to clean the blade - and this way he got more than 100 shaves with the same DE blade.

But there are probably very few people who bother to maintain a Razor Blade that only costs a few dollars. And it should also be said that Søren did it purely for the sake of the experiment ;-)

But most importantly, change the blade when you find it starts to drag instead of cutting cleanly. You're already saving a fortune on Razor Blades after switching to a Safety Razor - so remember to replace the blade in good time. That way you'll also avoid irritation.

Regards. Brose / Proshave