@Deborah84
It would depend on the type of guests you get and average length of stay. If you cater to a touristy or passing by type crowd and average stay is 3 nights or less, I'd probably say (1) NO (need time to clean, previous guests will not have checked out yet, room not available before the allotted check in time~) or (2) yes for a price (early check-in fee (I'd say 40% of the nightly fee sounds about fair) to be paid prior to arrival (using the "request money" function) and is non-refundable even if the guest ends up not needing the early check in, you had to pre-adjust cleaning schedules and whatnot to accomodate their request)
If you get a lot of early check in/late check out requests, this is something you should include this in your other things to note or listing description.