Always. I am spending a lot of time by reading the whitepaper, investigating the team members, checking the communities in social media. But the most important aspect of any research is an MVP or a working product.
Yeah, even if there is only a small amount of money involved, only a fool would invest in an ICO without the simplest idea about that project. I think doing an initial research about the project is the right thing to do first since it would more likely guide a prospective investor on deciding whether to invest or not. And as a rule of thumb, investors must first have a due diligence first on that project to avoid substantial losses that maybe incurred if they chose not to do it voluntarily.
For sure it is the most important thing one should do before investing, try to become very satisfied before getting in ICO, after research I think the next step should be inquiry, try to ask other people and your friends about it, try to gain each and every important information about market, it is much better to start with small amount of money.