Else If vs using If and second If

Can you please explain the difference between using Else if vs. just using an If and a second If??

If the choice is binary (true vs false), using a second if just makes you look stupid.

No-one wants to look stupid.

Using a second 'if' can waste time. If the first 'if x' was true, we know that x is true. Testing it again with 'if not x' is now redundant, so it's a waste of processor time.

The ‘else if()’ line is not executed when the ‘if()’ line is true.

Look at switch/case for a similar solution when simple integer comparisons are needed.