Reason number one
If the current devolution process was in place in any other area of Welsh life there would be uproar.
Imagine: Warren Gatland picks his team and makes a gameplan for the opening game of the World Cup but Martin Johnson and the suits at Twickenham refuse to let the Welsh players play an expansive game in the second half. Instead, they have to keep the ball up their jumpers in their own 22 until thirty seconds before the end, when Johnson will tell Gatland whether or not Wales are allowed to score.
That wouldn't be acceptable and neither is the current system of political devolution. A Yes vote means that Wales will be in control of our political tactics and gameplan. (And we'll still be part of the Lions squad when it comes to things like defence and foreign affairs.)
Reason number two
It's a vote about Wales, our country. It's not about politicians, government or the Assembly.
We need to have the courage and self-respect to run things that are already devolved to us by ourselves - just like Scotland and Northern Ireland have been doing over the last decade. A Yes vote reaffirms that Wales is as much of a country as these two places.
If you don't like the politicians we've got then vote in some new ones in the May election. Or stand for election yourself.
Reason number three
The Assembly's not perfect. But neither is Parliament (Iraq, cash for questions...).
At least the Assembly is full of people from our communities, working for Wales. The Welsh voice at Westminster is tiny and gets swallowed up by the 600 other MPs each looking out for their own part of the UK. Only the Assembly puts Wales first.
A Yes vote lets the Assembly run things that are already devolved exactly according to who we elect. A No vote keeps Wales at the mercy of civil servants in Whitehall and unelected peers in the House of Lords who have a veto over many things that the Assembly may want to do in areas that are already devolved, like health and education.
Reason number four
The vote is not about:
1. more tax - a Yes vote would not increase taxes or give the Assembly the power to raise taxes.
2. more politicians - a Yes vote would not increase the number of Assembly Members.
3. politicians 'grabbing power' for themselves - the power already exists at Westminster. The vote is about whether Wales should have a bit more of that power. Even most MPs think that we should and will themselves vote Yes.