How common is common?

From John Ramm - As I followed the Wetland boardwalk at Pentood today to the accompaniment of chiffchaffs calling and wrens churring I caught sight of a nuthatch. According to most bird guides this is a common resident (order 5) with about 20,000 - 199,999 in the breeding season each year. Clearly it is less common than a chiffchaff (order 6 - 200,000 - 2 million) or the wren (order 7: over 2 million), but as common as the redshank and curlew (order 5) and much more common than the kingfisher (order 4; 1,000 - 9,999). For myself, however, I rarely see the nuthatch and it gave me just as much pleasure as seeing the drake pintail at Newport bridge on Monday (order 2: 10-99 breeding pairs each year).