Recently former SNP leader Gordon Wilson proclaimed he was "laid back" about losing the 2014 referendum, because "Scots will back separation the second time round as Westminster will react to victory next year by scrapping the funding formula that gives them extra public spending".
This is a sentiment I've encountered quite often. The thinking seems to be that it might take two tries to achieve independence, and that it doesn't really matter in the long run exactly when independence happens.
However, I'm not laid back at all. Of course independence can happen later, but I fear the conditions will be much worse in twenty years' time.
First of all, there is still a significant amount of oil left, but when you look at the CO2 emissions, I personally find it unlikely that it'll still be legal and acceptable to burn oil twenty years from now. Of course it would have been even better if independence had happened thirty years ago, but there's still a good chance of using oil money to pay for the inevitable costs associated with dismantling the British state and building up new institutions.
Secondly, all the Westminster parties want to extend austerity and continue to dismantle the welfare state. It's also likely they'll start to roll back Scottish devolution, or at least the financial settlement associated with it, once the threat of independence has been fought off. The consequence is that it will soon not just be a case of maintaining the British welfare state in Scotland after independence (at the same time as it gets dismantled in England), but if independence doesn't happen till 2036, Scotland will have to reinvent the wheel because the UK then will be a neoliberal third-world country.
Finally, there's no guarantee it'll be as easy to be allowed to hold a referendum two decades from now. If the result is close, Westminster will probably think it was a close encounter with death and make sure that another referendum will never take place.
Because of all this, we need to win this time!