I change the blade after three shaves, regardless. If a blade cannot make three perfect shaves, it will not make it in my stock. Blades are too cheap to spoil a good shave and a morning. Bad shave = bad day.
Life is too short.
Life is too short.
I change to a new blade on each pass.
Never thought I'd hear that one, what brand of blade is it?
Whats it like having pubes for facial hair?
I change to a new blade on each pass.
I'm now in my 60's, and as my whiskers turned gray, they became pretty tough.
Anyway, this blade changing issue seems to arise when someone has a fixed notion that a blade should last a week or so, and in fact for them the blade may be past its prime after only two or three or four days due to personal factors. In that case the remaining days are subsequently less than satisfactory, as blade longevity for them doesn't match their expectation or what some other guys report.
Guys here will get 2 to 6 shaves, or more, per blade, all depending on personal factors to them. The average is probably 3 ~ 4 shaves or so. Factors are the brand of blade itself, lubrication, sensitivity of their skin, toughness and density of their beard/whiskers, type of razor, number of passes per shave, personal technique, and so on. Only the user can determine when swapping in a fresh blade is needed.
As to when to change blades; at some point, the blade will become 'dull' in that it will not reliably 'shave' the whiskers. 'dull' is relative, because a 'dull' blade is still very, very sharp and can easily cut you.
But the blade will only 'cut' --not 'shave' the whiskers. You will become aware shaving takes somewhat more effort; that the blade is leaving some stubble/uncut whiskers behind after a pass; that there is a little additional 'tugging' or 'pulling' that was not present the day before, that following the shave, your face feels 'prickly' or otherwise irritated. So be attentive and change blades accordingly.
The routine I've fallen into is 3 to 4 shaves per blade --that's two blades per week. I don't try to extend this, though I can get two weeks of great shaves with the old Personna*74's. That said, you should always shave with a blade that is in its' prime --blades are cheap and there's no reason to eek out additional shaves to save a couple of pennies.
I seriously don't get the 2-3 shave/blade experience. I realize some have extremely tough beards but I can't imagine that any quality blade can't go for 5+ CC shaves. I have been trying to get 5-7 and usually can with no problems and then I just feel like a new blade. Then I read about guys going 15, 20, 25 shaves (see http://badgerandblade.com/vb/showth...ual-quot-One-Blade-in-February-quot-Challenge) and similar threads and I wonder if I should give blades a little more time before changing. Wondering if MMMV?