Welcome to the Airtable community!
A table is a place to store data. A dropdown is a user-interface element.
I think you are asking when to use a linked record field versus a single-select or multi-select field. This is a design choice that depends on the type and structure of your data. Here are some guidelines
- if the choices are fixed, very well defined, and do not have associated data, a single-select is fine
- if you need to add new values on the fly, use a linked record field. You can add new linked records with new values without changing the base design. However, adding new single-select options requires altering the field definition.
- if you need to store additional information based on a particular choice, use a linked record field and store the additional information in the linked table
- if multiple tables need to share the same list of options, and the list of options needs to be kept in sync for both tables, use a linked record field
As far as having lots of tables, it is hard to evaluate that without seeing your actual data. If you have many tables with the same structure, you should consider combining them into a single table with multiple views.
