The only DE blade I have been able to get more than 3 shaves so far (without issues) has been the Personna Med Prep (5 shaves). Should have binned it after 4 though.
Honestly, 2 is probably the ideal number for me with most DE blades.
I won't shave again until the first of the month, so I dumped blades for the razors I will use first:
Hoffritz Slant: Personna Red
Gillette postwar fat-handle Tech: Feather
Gillette '53 SuperSpeed: Personna Med Prep
All had 3 to 4 shaves on them. When I go to a 36-hour shave routine once I start back to work at the office, I'll see more shaves on a blade and may have to replace them more often than 30 days.