Well, I'm not sure I can accuratly answer your question since the edge on my blades goes back to my noobie days around 8 months ago and probably gets better with the newer blades I added. Using mostly a different blade each day I may have used each about three times w/ too many different blades in between to remember the experiance with that blade the last time.
What I can say is that the different types of carbon steel will break down at different rates and the finer the edge, the faster it breaks down. Storage also plays a role in the rate of deterioration. Storing a blade in a container tht will not allow for air flow and/or absorbe mositure will have a faster oxidation than open air flow or absorbant material. That said, I purchased 5 straights 15 or 20 years ago at a local auction. The blades were in really fins shape with no rust or tarnish. I tried to figure out the straight razor stick nut with no internet or SRP to help me I didn't get too far. I put the blades in a paper covered wood cigar box and stashed it in a draw. Aout 8 months ago I dug them out when my son started shaving. They looked like they did when I put them away 20 years ago. One was a Pipe, one a WP&R Wheel, one a Wade and Butcher, one a Robeson and the last I don't recall the make of right now. I would asume they are different steel composition so the storage preserved them. Here's a pic of the Robeson (made ny Boler). I didn't do any Mass or other polishing to it befor the pic. Why did these stay so well preserved w/o any oil or fancy protection? Was it the cigar box? :shrug: This may be a good experiment for someone that has the time and patients. Has anyone tried parking their straights under a pyramid yet? :w I am curently storing my blades in test tube stand that holds 50 blades, tooth brush stands and some in razor rolls in a safe with lots of large silicone gel packs. No issues of rust. Previously I had some in the china cabinet for a while just to keep them out of the way and I notices corosion on the edges after a few weels. I have two tool boxes of presision Tool Maker tools w/ the silicone packs and the tools are as good as they were 17 years ago when I packed them up while other hand tools in the same room but not the tool boxes rusted. I am sure this will relate to the edge of our blades and am interested in hearing about other success stories where the process did not involve oils even though oils do provide a solution as do others like Tough Glide.