I use Shimano LC1500 reels. They have line counters on them that keep the plugs at the same distance out.

Bobber stops at what ever distance you prefer also work. The only problem comes if you tangle your lines or break off somehow. When you re-rig you bobber stop wil no longer be in the right spot.

The problem with counting passes on the reel, beyond the paying attention already mentioned, is that both reels must be the same model as well as having the same line. If not, they will not be out equal lengths.

I was not sure buying the line counter reels was worth the expense when I was buying them. Now I am convinced it was some of the best money I have spent on gear.