SO Quote Expiration

Hello All,

 We are looking to change the quote expiration default from 999 to 30 days, currently when quote is created it expires in 999 days so the user has to change to 30. Does anyone see an issue with this change and once changed to 30 will we still be able to change it out further if need be.

Also, is there anyway to automatically delete expired quotes instead of deleting manually. 

Thanks