Anyone know how long usually it takes for ICO projects to list their tokens on an exchange? Is it different with other exchanges?
there is no certainty, everything depends on the team behind the project.
By the way, I bought several altcoins in 2018 and until now there has been no news when these coins will be listed on the exchange.
Have you done a lot of research before? It looks so horrible to see that. if the team wants to pay the listing fees and the coin can be listed on at least medium exchange site. But most of icos are wanna holding their money rather than spending it for liquidity.