Fly line.

I seen a SA oike musky taper start cracking after 4 weeks of use. If ya step on it and fishin in shale or rough stream bottoms its gonna happen. I very rarely clean my lines. I have a streamer express line that seen more casts this summer outta my 10wt. than most cast in 5 yrs. I havent cleaned or dressed it. And its goodas new, well ok its a little dirty....

extreme temps... lines with crack if left in the hot or cold (trunk of car)
 
water condition... dirty water= dirty line... ice= freeze thaw in a pourous material (think pot holes)
 
depends on the brand/ model

Try a top of the line, I believe the airflo are the most durable out there? Maybe try one of those.

I've been throwing a SA GPX on my 4wt for a year and a half, bings...in that time, when it wasn't on the water, it was in the trunk of my car...while it's not like fishing a brand new line, it's still holding up just fine, and I have no immediate plans to replace it.

I'm thinking you just probably are punishing your line more by fishing on all that shale and in harsher conditions than I use my line in.

Shoot an email to SA, see what they have to say. Worst case, they may tell you you fish too much...best case, they send you a replacement that you can use for the next 6-7 months.

ORIGINAL: bingsbaits

Last one was a Scientific Anglers, Aircel, Trout 6-7 wt.
Got about 6 months out of it. Still using it but will get a new one come spring.

Line before that was a SA GPX 6wt.Got 6-7 months out if it before it was cracked all to heck.
Extreme conditions from last winter may have been the demise of this one. Did throw alot of frozen rope.

Bings; try matching a rod up with a line that will allow you to cast/fish with out much stripping in when setting up for next cast... this will prevent wear and tare... especially in the winter months...

For lines, I always liked hardy but it seems as if they are making them different now. Haven't tried the new ones yet. But they have always performed well for me.

Cortland precision is my most recent line and seems alright so far...

Tight lines...

Long story short.I have a Scientific Anglers aircel on my 7 wt. Kids got the wife a kitten for her birthday. I was cleaning my line last week. Kitten thought line was something to play with, bit the line in half with one stroke. Didn't kill the cat, but wanted to. Seriously I do think that the shale and slate are major contributors to line damage. I like the SA aircels. Inexpensive, but don't stand up to sharp cat teeth!  

from fishing a few different brand lines this is my conclusion.

i found Orvis line is bigger in diameter than other lines of the same weight. because of this i had to shorten my backing. also i have found orvis lines get stiffer in colder weather.
Cortland i find stays limber in cold weather. Cortland has a chart about what lines are best for colder weather and which are for warmer climates. i've had my 444 lines hold up the longest.
SA lines get a little stiffer and retains coils in colder weather. they do seem to have a harder coating. like cold said, even though mine developed a few cracks it was still usable for some time.
i got a new WF Sage line. it stays soft in the colder weather and shoots line out like any i have tried. how long it will last i'm not sure.

some things i found that damaged my lines.
1. stepping on it doesn't help it!
2. i found to not over spool your lines. meaning that when winding in fly line make sure it doesn't scrap against the line guard on the reel. i believe this scrapes the coating off.
3. keep insect repellant and such off the fly line.
4. in freezing weather, besides using lip balm on the rod guides, i coat a good section of the fly line. this keeps water off the line longer and keeps from freezing up.
5. speaking of line guards, check to make sure that the guard isn't worn or scratched. i had to replace my line guard on my original battenkill reel, wore a groove in my graphite clearwater reel, and starting to wear a groove in my mid arbor which isn't replaceable. not sure why mine wear, it must be me because i havn't heard about this from anyone else and even Orvis couldn't believe i worn the guide in their reels.
5. i'm sure the cold weather and ice puts some undo wear on it also.
6. my fly lines stay in my vehicles most of the year but they are in a case and i keep them out direct sunlight.


i admit these are the only brands i've used mostly being i can usualy find these on sale.
KJH brings up a good point, it comes down to personal choice. 
i'd rather have two or three new lines for the price as compaired to an expensive line that lasts just as long. same way with my waders and wading boots.

2. i found to not over spool your lines. meaning that when winding in fly line make sure it doesn't scrap against the line guard on the reel. i believe this scrapes the coating off.

+1

If you're using a LA or wide reel, this is more of a concern, as you can get a bunch of line built up on one side or the other of the spool if you aren't paying attention. I put a nice scrape on a new line once by doing this.

Dan see you at the show friday.

Good info from all/ Bings I hope it helped