Here is maestro Frank Ford of Gryphon guitars shop, the fretted instruments heaven, who gives a wise suggestion about "why" changing strings regularly...
I recently discovered, thanking John Renbourn's well informed hint, as well, the superb Rotosound Super Bronze B12 "piano strings".
"A while ago, trying out different bronze strings, I came across some old Rotosounds in black and red packets that I had somehow managed to hang on to for years. They sounded really good, bright and well balanced but with a rich tone. The company were amused to hear that anybody should still have strings going so far back but assured me that, several packet designs later, their new strings were still the same quality. Rotosound bass strings have a high profile world-wide which may have overshadowed their guitar strings. James How, who founded the company in the fifties, engineered a new type of string-winding machine that was a step ahead of the industry and all the strings are produced to the same degree of precision. In addition to the phospher-bronze round wounds, Rotosound also make guitar strings in the piano string design. That is with the wrap wire stopping short of the ball end so that a section of the core wire is exposed and only the core wire comes into contact with the saddle. These strings are called Super Bronze. It is actually an old idea and I have a feeling that the very first steel strings used on the guitar in the 1800’s were like that. The gauges for both types of string go from 060 to 018 covered, and 026 to 008 plain."
Amazing sound improvement on my Lowden S-35 RIO, Martin 00-21 and Harmony Sovereign H-1260 (see above pix) acoustic guitars.
Well, I do!