A method of checking a new entry in a calendar application having a cache that includes a first subset of existing entries falling within a first date range. Also, an electronic device implementing the method. The method includes determining whether the date of the new entry falls within the first date range. If so, the method determines whether the new entry directly conflicts with or is adjacent to one of the existing entries in the first subset, and provides a notification if appropriate. If the date is outside the first date range, the method creates a new calendar cache including a second subset of existing entries falling within a second date range around the new entry date, determines whether the new calendar entry directly conflicts with or is adjacent to one of the existing calendar entries in the second subset, and provides a notification if appropriate.