Is there a way to create entry limitations to where a user can only schedule themselves for a certain number of dates?
Date fields do not have a minimum or maximum date property (like numbers).
Depending on your requirements you could probably do something with the validation property. An example where someone posted an answer to validate the end date not being later than 30 days after the start date: date column validation
more info on date validations: https://social.technet.microsoft.com/Forums/office/en-US/b4a57b7c-0938-42d8-96f6-f7e6ef21876d/custom-validation-in-sharepoint-2010-list-for-datetime-columns?forum=sharepointgeneralprevious
- You can only compare column values to one another in a list level validation.
- A validation formula at the column level cannot include any other columns besides itself. For example, [Column1]>[Column2] is an invalid formula and SharePoint will not allow it to be used at the column level. In this case, you want to use list-level validation.
- There is only one formula available at the list level.
- The formula syntax is similar to that used in Calculated Columns
There are a few dozen functions available - I have not tried every one. One interesting thing to note is that SharePoint 2010 would not allow me to use the TODAY function, even when validating a Date field. [DateColumn]>TODAY is not a valid validation formula.
The validation is effective for every user. If you want to make a difference per user (so user x gets date 1-3 and user y gets date 4-6) this will be much harder.