I remember hearing in the passing somewhere that a nikkah is only valid if it is consummated within 3-4 days I think, I do not have a valid source for this neither can I say I know this for sure but it's worth the research if someone is about to do the whole nikkah first then rukhsati in a few months/years.
If anyone knows more then feel free to correct me since I'm not too sure :)
That is a load of bull. People here like to joke around saying walima jaiz nahi hota unless you’ve consummated, that is just a misconception, there is no such condition attached with nikkah.
Having said that, I’m sure most people rukhsati or no rukhsati do manage to consummate during the gap period, I know I would..