Hm well i havnt tried more than 1 week per blade so...2 months per 10...thats around 1yr and 8 months per 100 pack(unless i got confused in maths)...damn thats good value now i think on it most cost about 10-20$ Per 100 here and thats about the cost of one packet of cartridges...wich doesnt last long at all for me ...
I normally get between 20-30 shaves per blade. Using an average of 25 per blade that is 250 shaves. That is over 8 months (8.33). At 20 shaves per blade that would be 6.67 months. I don't often get 30, but almost always at least 25 or more.
I have 3 razors with blades in them right now. One @ 21, the other two @ 7 each. Going to try and get through Friday on the 21 anyway. That would be 28 on that blade. That is a pretty common ending point.
Depends on the blade. I am on my 6th blade since the start of the year so I am heading for 27 weeks for 10 as an average. Derby the lowest and Astra SP the highest amount of shaves per blade. Previously I was at 1 per week => 10 weeks of daily shaves.
Time to do the math. I shave 3 times per week. I get an average of 7 shaves per on my current 7 o'clock Permasharp. So about 70 shaves per 10 so approx. 23 weeks.