
Mark H. answered 06/17/19
Tutoring in Math and Science at all levels
Another opinion:
In my experience, "I'd" is most often seen as a contraction of I would. Compare this to "I'll", meaning I will.
The usage is either future or conditional, and normally involves another verb
Examples:
I'll go to the store = I will go to the store
If I had a car, I'd have gone to the store = ...I would have gone....
In the above example, we can see how "I had" could become "I'd"----as in "If I'd a car". In my experience this is not considered good grammar.