Should I apply for Singapore PR if I am going to live in Singapore for another 2-3 years only?

If you do not stay in Singapore after getting a PR, you may face problems while renewing your Re-Entry permit. PR status is not permanent, and you need to be living and making contributions in Singapore to enjoy PR benefits, or else it may get canceled in due time.

In case your plans are short term, then you need to really consider whether you want to apply for PR or not.