For example, you build the first level of the Magic building for 2000+5+5, don't get the slow effect, you're a little disappointed, but not too much, because the next day you can choose the option to rebuild this level of the Magic building for the same cost and resources.
New 5 spells will appear randomly, which haven't appeared before. (When all possible spells have appeared, the cycle will close and repeat). This is a very strategic feature, for example, you build a Town Portal, learn it, and use it, then you rebuild the tower so that the enemy doesn't get it.
The opponent will get tired of rebuilding it, because it takes time and a lot of resources.
Rebuilding in this way seems like a freebie, but if it's organized the way Scorpiona suggested, it's quite acceptable:
So, let the Grand Magus building be built from scratch, for example, you spend a day destroying the building for a certain amount, and then rebuild it from scratch!!!
Rebuilding as an additional option is also a good idea.
