Consumers lashed out in December with a rare double-digit monthly increase in credit card spending, but they were back to watching their budgets in January. Reserve Bank data showed the value of purchases on credit and charge cards fell 13.8 per cent in January.The $21.4 billion spent on cards in January was the smallest monthly spend since June last year.Card balances also fell from $50.1 billion in December to $49.1 billion in January. CommSec economist Craig James calculated that the average card balance of $3146.90 was a four-year low.James said cardholders were using an average of 34.5 per cent of their available credit limit, the lowest level for 12 years.MWE consulting principal Mike Ebstein said one positive for the card industry was healthy growth in card account numbers, which now stand at 15.6 million.