calculations & relations

Working with FM I have learned to avoid calculating fields due to speed constraints.

Working with Servoy I would like to know the following:

I have some fields that I (want to) fill with values from different fields. Nothing fancy but there is some work to do for the processor.

Values are both numbers and text strings.

What is wiser: use a calculating field or do the calculation on closing a form (maybe based on changes but then I have to catch changes on all fields, also related onces).

That kind of simple concats of data shouldn’t be any problem.