This is another cautious budget from the particularly cautious and slow-moving Baird government.

Mike Baird and his Treasurer, Gladys Berejiklian, are unlikely ever to get the state's finances into bother, but nor are they likely to win any medals for innovative, agile reform, or even for achieving the most with what they've got.

On the positive side, their sober and sensible response to the state's property boom - act like it isn't happening, try not to ease up on your spending restraint too much and take the extra revenue straight to the bottom line - is in marked contrast to the West Australian Liberal government's profligate response to its mining boom.

It - and most of the rest of the state - acted as though the boom would never end, and now the government is big trouble, financially and politically.

Then, they were far too prosperous to resort to the politically unpopular "asset recycling" of Baird and Berejiklian - selling off utility businesses that no longer needed to be government-owned so that new infrastructure could be built without adding to government debt.

Now, however, the humbled Barnett government is copying poor old NSW.

This time last year, Berejiklian was expecting a budget surplus for the financial year just ending of $2.5 billion. Now she thinks it's more likely to be $3.4 billion.

How so? Then, she was expecting the government's federal grants, tax collections and other revenue to grow by 4.3 per cent. Now, she expects growth of 6 per cent.

Then, she was expecting government expenses to grow by 3.8 per cent; now it's 5.4 per cent.

What's the point of running ever-bigger budget surpluses? They are used to help finance the year's spending on new infrastructure and so reduce the need to pay for it by borrowing.

This reduces the risk of the state losing its AAA credit rating.

The story is expected to continue in the coming year, 2016-17. With revenue likely to grow by 4.4 per cent compared with expenses growth of 4.2 per cent, the budget surplus will rise to $3.7 billion.

So successful has this government been over the years in ensuring its expenses grow more slowly than its revenue that Berejiklian is boasting proudly that she has got government debt down to "virtually zero".

But it will increase in coming years. And, of course, this is just for the government proper - "general government" - and doesn't include the debt of the government's various "trading enterprises".

Even so, the state's overall debt - government proper plus its businesses - is not high. Never has been, really.

When you consider the amount of much-needed infrastructure that has yet to be built, it makes you wonder why - despite its low debt - the government worries so much about having its credit rating down-graded.

Why let a couple of American rating agencies - whose credibility was irreparably damaged by their part in the global financial crisis - have so much say over the adequacy of the state's infrastructure?

Because the Baird government always plays it safe. Let this be a comfort to you as the length of your daily commute gets ever-longer.