You take part in a ICO campaign because you had made research and thought that the project is worth your effort, so when you get paid at the end of ICO you would make appropriate decision on the tokens. ALL depending on your financial needs you could either sell them right after the ICO for cash to pay for daily expenses or hold them for longer time in hope for better gain. These tokens were given free for your campaign effort , so making either decisions , the end result is still the same, and the difference is only the amount of profit you get.