Caterbook has special built-in Extra "Item types" for both early check in, and late check out.
Using these Item types, it would be possible to create several instances of the extra, but with different prices - for example "Late check out 1 hour" = £15, "Late check out 2 hours" = £25.
Additionally, these will display with a Clock icon in the relevant arrivals or departures panel, to give staff visibility of any reservations that these extras are booked for.
As with other Extras, these can be sold online when a guest books on your website, and you can also select which rate plans they can be sold with.
We've also made it possible to receive an email to alert staff that a web booking has been made with an early check in / late check out extra - in case it's a same day booking or otherwise needs to be confirmed. You can select Extras from the Filters menu in your email template: