I want to understand the process of PCB design using a software like Altium. I have come across two approaches as follows:
Approach 1: While making the component parts library we make the footprints of the component slightly bigger in size from that given in the component datasheet. Later we use these footprints as the PCB pads in the PCB design. So in this approach if a specific part is used multiple times on the PCB then for each instance we will have the same pad on the PCB as we would be using the footprint of the part as its pad on the PCB.
Approach 2: While making the component parts library we make the footprints of the components of exactly the same size as given in its datasheet. We also make a library of pads of various shapes and sizes. Later when a part is used from the library in the PCB then at that point we get appropriate pads from the pads library for the pins of the component. So for each instance of a specific part that is put onto the PCB we can use different pads as needed for that specific position.
I want to understand which of the above two approaches are correct, especially for the case of SMD components and PCB design.