blade changing frequency

[KollegeKreed]

I use a new blade every time I shave my face since it seems to be one more step in shaving sensitive skin. However, starting to use the Fusion for the chromedome, I can't afford to change the $3.50 razor every other day, so ill end up using that for at least 2 or 3 shaves.

[Asher]

depends on the blade for me.  but now that i'm using fusion power blades, the current one i'm on is at shave 6 and going strong (i shave my head once a day, and i have coarse, thick hair).  so that's at least a week i'm getting out of this blade.  i don't recall who said it earlier in this thread, but dousing your blades in a little rubbing alcohol after usage extends their lifespan a ton--i'm like the poster boy for blades+alcohol on this site. 
  i do think that you can 'help' your blades though, too.  like, when i use a good amount of headslick on my dome, the blade cuts better and (i think) has less friction, and thus, less wear.  i find when i use less shaving product (creams, whatever) and shave out of the shower, my blades run out quicker.  take it as you will. 

[blondeguy]

I can get away with using the same blades for a long time, but I generally start feeling it getting dull after a week, so Monday is a good time to swap them out for new ones.  It's usually a noticeable difference in shaving speed and quality.

[xnewyawka]

Since I started leaving a day in between shaves, (though not all the time, lol) I am getting a good 7-10 days of use from a cartridge. I also change off between my HB sport and classic, so it stretches pretty far.
And like Asher stated, I also believe it's good to make sure you have plenty of your favorite cream or gel to reduce friction.