Update an existing (animated) model I have one .blend project where I've imported objects via .dae files.
I've set up a scene and made animations etc...

Now there is a request to modify details of one or more object.

Question 1:
Is there a way that I can replace my existing model with a newer version where I keep the location, rotation, scale and animations?
Because now I need to delete the object, add it again and animate it again.

Question 2:
For future projects, how do you set up a blender project to overcome such problems?
There are a lot of ways. Two simple approaches (assuming you are talking about static meshes):

Switch the mesh in the Properties window - Object Data:




Or if you have LocRotScale keyframed, switch the action in the action editor: