Can I omit "for" and just say "over 5000 years" here?
Native speaker’s answer
Rebecca
When we are talking about time, we should include "for" (or "since," depending on the sentence) to specify the length of time. Omitting "for" would sound unnatural in this context. Ex: This cafe has been around for over 30 years. Ex: My parents have been married for 20 years. Ex: I have been playing hockey for almost nine years.