@bruce.button
Basically there is not much memory usage difference using a TPageControl with many pages vs using many TForms.
If you know, using TForm, all the forms will be created and loaded into memory before you show them, unless you disable its auto-create behavior. Even if you close the form, actually it just go hiding, the memory is not freed. Unless you call TForm.Free or set caFree in the CloseAction variable.
Most of the computers nowadays have 4 GB of RAM or more. Memory usage of a form has very little impact in the whole system.
But if you really care, in your case I think you can consider to close the Dataset if you switch to other tab or closing the form, and open or reopen it when needed.
About TFrame, I don't against it. But just what dsiders said, it needs extra effort. It can be tricky in some cases, try it and you would know what I meant.
As a programmer, you should be open, try and learn everything if you have the time. Each of the components has its own pros and cons.