Hi Caitlyn,

I would recommend the following for making fields read only:

1. ACLs - Access controls are great because they run on the server and apply to both forms and lists. However, if you need the mark something read only based on a change on the form, they won't work.

2. UI Policies - These are nice because they require no scripting and you can order them. They also support pretty complex conditions, but they only really work for a condition or the opposite of that condition, so if you have a number of different conditions that have more than 2 outcomes, you might need to use a client script.

3. CS are all scripting so they can be more difficult to work with, but they can do everything a ui policy can do and more.

From your description it sounds like you might still be able to use a ui policy. Could you do something like:

Condition: Stage is 1 or 2

Action: Field is read only

And just separate it out in its own ui policy.