How many past morning exam papers should you do?

I know that it is very important to do past morning exam papers but how far back should you go? Is the past 5 years enough? I also suppose going further back probably makes less sense as the curriculum must have changed a lot since then?

In another topic a fellow poster mentioned you can obtain a document from IFT website (go to Free stuff > Other stuff) that mentions the relevance of past exam questions to 2018 curriculum. So as long as it’s relevant, practice as much as you can!

I took 10 and each 3 times.