Give or take, how long do you wait to receive your coins? At what point do you start to become suspicious?
It depends on the coin network. If it's Bitcoin then the fastest transaction speed is around 30 minutes for the expensive transaction fee and for the cheaper fee would the more than a couple of hours, otherwise, most altcoins do have the speed of
Around 5 minutes and must of them will be lesser
than a minute.
If you still don't receive the transaction then wait for at least 24 hours.