I counted 106 at my course - mowed with a step cut. The obvious negative is the maintenance. It also looks silly at certain points.
Nonetheless there are positives.
Part of the reason for all of the boxes is to accommodate high level events - our superintendent's revenge event plays at over 7700 yards. On many holes, one cannot even see those tees in normal play. When someone who can handle that length plays the course it is fun to watch - they essentially hit the ball to the same spots I play from 70 yards ahead.
At the same time, many forward tees have been added over the years - making the experience more friendly for beginners and providing a fun alternative for emergency 9's.
Some of the added tee boxes really add to the fun - different angles off the tee have a surprising effect on how a hole plays and it is nice to spice things up at times. Our 18th hole (a par 5) is a very good par 4 from the front tees. Some of the 400 yard par fours make interesting driveable holes from the forward tees. You can play each par 5 as a very long hole or as one where you are trying to reach in two.
The course is routed so that the natural walking path takes you to the 6700 yard tees most of the time so the flow from a walking perspective is not really a problem.
It might not be my choice from a purist perspective but I am not one to let purity interfere with fun.
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