Clarification on Option Spread

Refering to the option spread we had discussed on Corn i.e. Buy July 250 C & Sell 270 C for debit. Now that corn is moving, and the spread is widening, how would this trade play out.

Do you hold the spread till expiry? If so does it automatically settle at expiry or do you close it by selling the long option and buying back the short one? At what point in time would it be beneficial to close it before expiry?

Thanks
surjs