I am thinking a brand may hold up for a different lengths of playing time, even on the same violin, viola or cello, for different violinists, violists or cellists.

1. Wouldn't what you play and what is expected from the strings make a difference how long they last? If you play songs that require aggressive bowing, wouldn't that wear strings out sooner than if you are more typically playing slow waltzes, love songs, a lot of pop, etc? Wouldn't that same brand, on the same violin, by the same violinist have a different lifespan on that set, based in the type of bowing required for the music typically played?

2. Would the quality the playing affect the lifespan of the strings? If you are new and still learning bow control, would that affect how long the strings last? Bowing at an angle and too much pressure, etc. Wouldn't that affect how long a set will last? Isn't that why they usually suggest beginners use inexpensive strings?

3. How often and for how long you play during that same, maybe 6 month, time frame, vs another violinist who plays more frequently or leas frequently, would affect the lifespan of a specific brand of string, right?

So, maybe lifespan time for violin, viola and cello strings should be referred to with playing time frames, not calendar months? Like a tractor, it shows hours of use. Maybe when we talk about how long the strings last we should be talking the playing timeframe, including practicing, not just performing if you are a professional. So, if you generally play 21 hours a week, or 3 hours a day or approx 90 hours a month, and you had to change them in 5 months, that is a lifespan of approx 450 hours for those strings. The approximate time actually spent playing those strings.

When someone says they change their strings every 5 months, it is actually relative to their playing schedule and how they are bowing on them. 

My cello just received a checkup last week. I just got it back yesterday. It needed new strings, also, so I had the shop put new strings on, also. I had a new set of the green label Evahs, that sound so great this cello, but, I decided to let them select a set, and hold onto my Evahs as replacements, when needed, The Evahs are a bit expensive, especially their cello strings.

They sold me the cello a few years ago, and David, the cello guy, knows exactly what I like, warm and sweet. Luckily, that is what my Mikey G likes, also. David knows I am particularly fussy with the A string,

Wow, they put a great set on. I am hoping they last a while. The Evahs held up really well. If these do not hold up as well, it won't save me money because I will have to change them more often. It is a mixed set. The D and A strings are the same and the C and G are the same, if I remember correctly, I have it written down, but can't remember which brands off the top of my head.