Difference between Occur and Incur
Occur: to happen, to take place unexpectedly.
The lunar eclipse occurred while I was traveling to Australia.
The corruption of the bank occurred during the 1980s.
Incur: To acquire or come into (something usually undesirable).
Peter incurred many additional expenses while he was studying abroad.
Any extra cost will be incurred by the client. (the client will have to pay)