Year old braid. Hardly used. I go fishing today and all of a sudden I'm breaking off on the hook set?? Weird because I've never had this problem. Checked line and everything. Suggestions please!

Check your guides

Maybe your hooking into gar or pickerel. Sometimes I'll set the hook on a gar or pickerel and never even feel the weight of the fish before their teeth cut my line.

Neither of those in the water I fish. Just a pond. I always check my guides but ill check again.

If you don't cinch the knot really good and cut the tag end too short it could be slipping.

Check the end of the line to verify whether line is breaking, or if knot is simply slipping free.

Year old, hardly used - I agree with potential knot slippage. The braid will still have a slick coating (depending on the brand and type), which could be at issue.

 

Also, are you talking 10, 20, 30 pound test (or higher)? Or the even thinner 5-8 pound test braid? I'm going to assume the former as I don't know many who use under 10 lb test braid. Reason I ask is whether or not you have a massive hookset or not.

 

I tried 6 lb braid once. Broke on me all the time, LOL.

I have 10lb PP. I almost always use a Palomar and have absolutely no problems like this what so ever. I tried a uni and did the same. As far as the hook set, nothing crazy lol just my same old hook set.

One time I noticed the knot was still at the end of the line after breaking off.

Hmmm...see if it breaks with manual pressure.  Alternatively, try a double palomar and see if that helps.

Reel Magic line conditioner for all my reels if they are going to sit for a while.  Heat is not a lines best friend.  You might have gotten a bad spool of line.  Your knot may be slipping into that groove on the eye of the hook.  Can't say as I have ever broke off any of my braid on a hook set.  Most of the time I'll straighten a hook out before I break line.  If it were me, I would put a fresh spool of new braid on and throw that old one away...