Most efficient way to swap between models?

What is the most efficient way to swap between in game models, given the two scenarios:

1) Model 1 -> Model 2 -> Model 3
2) Model 1 -> Model 2 -> Model 1 -> Model 2

Would it be better to just show hide the objects with activate/deactivate? Or is it better to destroy the old one and instantiate the new one at run time?

Would the answer be the same for both scenarios?

 

If memory is not a concern, then have them all loaded when the scene loads and
then just activate/deactivate when required.

If memory is a concern, then let
them be instantiated at the right time, however, depending upon the kind
of model you are instantiating, there could be a drop in fps.

 

For both of your scenarios:

1. Destroying and instantiating is the least efficient. Avoid it if you can.
2. Activate/Deactivate is much better.
3. Object pooling is as good as #2 and looks a lot like #1.
4. renderer.enabled = true / renderer.enabled = fasle is the bestest, but might not work in every scenario.