One of the problems that Access developers have when they design in a bound environment is that they put combo boxes on forms which show a big list. This is not only hard to navigate once you start showing hundreds of records, it also causes the form to take longer to load, especially when you upsize to SQL Server.
A better option is to include next to the combo box an ellipsis button “…” which pops up a lookup form.

Figure: Developers typically return all records for a data bound combobox field, which can increase form load time and put unnecessary strain on the database