I tuned my kite today as I suspected my front lines had stretched. I was right they had stetched 8cm in only 3 months. Anyway I sorted that out , but it got me thinking do bridles stretch as well?.

I havent checked on my kite, not exactly sure how to check as if it has stretched
evenly how would I know?.

Has anyone got any experience or opinions on this?

yep, happened to the bridle lines on my bow kite too
I also noticed considerable wear&tear on the lines - particularly where the pulleys are situated.
I do quite a lot of kiteloops as well & so this increases the degradation rappidly.

ended up having to change those lines (where the pulleys 'glide' along) more than 2times during season as they ended up snapping! keep an eye on that specific area

c ya!

Yes, if you throw your kite about alot the bridles and pulleys will wear big time. I always have a spare set of pulleys and I make up my own bridle lines (not recommended) from old spare lines that I have.
To answere your question. If your main lines are the same length and your kite pulls one way then one bridle line may have streched.