Braid to braid – opinions wanted

So I borrowed a couple of rods to a friend. He tangled the lines while trolling and cut off about75-100 feet of line from each reel. Not happy. Anyway, with braid being so expensive I’d prefer to just add the 100ft back by uni-to-uni knot. Is this a dumb idea or no? I figure I frequently do this with my braid to fluoro leaders, why not a braid extension. The one thing I could see being a flaw is the knot becoming weakened by repeatedly going through the guides.

Thouhts?

I’ve done it plenty of times, never had it break off at the knot.

I’ve done it a few times. I use the double uni, 7 turns on each side

I agree with the other guys. You’ll be fine with a double uni knot.
Or, make your buddy buy you new spools of braid……