Number lookup tools can be useful, but I wouldn't rely on them completely. In my experience, they sometimes identify businesses or known spam numbers, but many private or newly created numbers won't show much information.
If the messages seem suspicious, it's usually best not to reply or click any links. I normally search the number online, check whether others have reported it, and block it if it looks like spam. For legitimate contacts, they'll usually leave enough information for you to verify who they are.
The lookup tools are a good starting point, but common sense and caution are still the most reliable protection.