Don't worry too much about it. You can renew the ME/IR up to 3 months prior to expiry or get it revalidated once its expired (I hope i got those the right way round). The only advantage of renewing is that you can do it in an approved sim (for the IR) the revalidation must be in an aircraft. The hoops you have to jump through for the aircraft flying on both accounts is fairly similar. Engine failure, steep turns, stall recovery, ILS, NDB, maybe some other failure (gear) at the examiner's discretion.
Hope this answers your question.