It is a good idea if you know how to understand whether the project has future or it will become a success, otherwise you will only lose a ton of money for investing to some fail ICO. The first deciding factor, of course, is the team behind the project. A project with a hardworking team has a greater chance of success than a project with a great plan but doesn't have a great team. Trend is also a good deciding factor when picking a ICO to invest with.