Three years may not, in fact, be anywhere near a reasonable threshold given the buying power of European and Japanese clubs. And that's what is driving this changing landscape.
Blokes arrive in Europe on lucrative club contracts and before they know it — as long as they haven't had their eligibility captured before they arrive — suddenly find themselves in the frame to play for the nation in which they live. That's it ... turn up and suddenly be French. Or English. Or Irish.
There are some fairly extreme examples of this which highlight what a nonsense it is. Josh Strauss and WP Nel have both been named in Scotland's squad and neither has played for or is even yet eligible. Both are South African, taking up contracts with Glasgow in 2012. The timing was significant as it was calculated that they would both qualify with just days to spare.
It's clinical and there is now, finally, outrage in the north that good, locally developed players are missing out.
What no one likes is the planned element to it because there are what have become known as project players all across Europe. These are, essentially, players who were jointly targeted by club and national union.
As an example, former Chiefs midfielder Bundee Aki's contract at Connacht in Ireland is thought to be financially supported by the Irish Rugby Union who see him as a potential test player.
The problem is that lines become blurry. It feels that test jerseys are being traded and that club rugby will struggle to differentiate itself from test football. The credibility is questionable and the problem is global.
France have two players in their 31 on residency; as do England and Ireland. New Zealand aren't guilt-free as Malakai Fekitoa and Waisake Naholo qualify on residency grounds.
No wonder, then, that World Rugby boss Brett Gosper said recently the topic needs to be put back on the agenda.
