The break and add-on in my tourney came after 6 levels. It was only 10BB, but it also only cost 1/5th the buy-in ($20 in a $100 tourney.)
Also, we had 20 minute levels. Pretty much everyone took the buy-in.
(Using past tense because I haven’t hosted a tourney since COVID.)
As a practical matter, this just made it a $120 tourney. But for some reason it was much easier to get people to buy in for $100 at the outset and collect $20 at the break than to ask for the $120 up front. People are funny that way.
It also had the subtle benefit of keeping some of the worse players in the game. If you gave them more chips up front, they would likely blow them and not last as long than if they got a bump after the first six levels. Unconsciously, if they got short as the break approached, they would tighten up in anticipation of the add-on.
Such players would then donk off their add-on pretty quickly most of the time. But as a host, one of my goals is to make sure almost everyone gets a couple hours entertainment. That makes it more likely they come back. If they’re out the door in 60-90 minutes frustration sets in and you lose people.
I guess what I’m driving at is: you’ve got to decide what the true purposes of the add-on are. To get more money in the pool? To help people play longer? Something else? Only then can you really decide what the price and value of the add-on needs to be.
(Also, if you are allowing full rebuys up to the break, do you still offer an add-on?)