In fact I had bad experiences with ICO's, I bought many of it at a high price in the initial selling stage and when it was listed on the exchange after a long time it was low price and i lost a lot of money, in addition to that many of it is scam. They make big advertisements and most of the ICO's are false and I didn't make any profits from it and so I left it permanently long ago.
Those happened because the project you invested was trash.
Good projects see a price increase or a price stability on their Initial price at least.
If the project is good and there is a development on going on the background the price is going to increase for sure.