Change the fluid.
As long as the lines are not leaking I would say leave them alone.

 

Interesting answers guys. I change my fluid once a year with dot 4. Lines look fine. My old car was a 1992 and I never worried about the lines on the track

 

I have an '00 ran winters for a few years. Last winter swapped out for SS lines. I cut in 1/2 one line just to see what it looked like inside and how it was holding up after all these years. LOOKED AWESOME. It's an outer rubber then a braided middle and inner rubber. If you aren't seeing any cracking in the lines you are FINE.

 

Thank you gents. Will inspect the lines again when I flush.

 

It's not always the quality of the line though, it's the heat fatigue of the crimp joint. See here for another OEM brake line failure:

https://www.s2ki.com/s2000/topic/1012717-a-close-call/

 

Like everything else..."When in doubt...change it out"

\rlr
Carolina

 

I guess age isn't the only factor, that car was an 07. It probably would have had a much lower chance on a street driven car though. New lines are relatively cheap, and an easy DIY job.