Why is it that the "age" is used as an uncountable noun in some cases and as a countable noun in other circumstances?
Now the market is not booming, and the employers are switching their schemes to make sure they pay less and their workers get less too. The problem has nothing to do with too much tax or too few incentives. The problem is that security in old age depends increasingly on the vagaries of the stock market.
If you have hobbies, you mix with a wide variety of people through that & often socialize with them. If you work somewhere & go for a drink after work, you probably do so with people of a different age to you within that.
Examples from OED:
he must be nearly 40 years of age; children of primary school age, his voice improves with age.
Here "age" is uncountable.