Clubs differ in their organisation and ethos - some exist purely as match-playing entities, others have a thriving programme of internal events. Indeed some clubs close entirely over the summer. Equally, different clubs will strike different balances between the wishes of individual members and the pursuit of glory for the club as a whole. Nevertheless it is possible to generate a code of practice for members which can be summarized by:
Be honest
If your club deliberately builds its teams around the wishes of its members, be honest about your likely availability when this information is being collected. Neither asking for a full place in a team, but rarely being available for matches, nor stating that you only wish to play the odd match, and then complaining at Xmas that you have hardly played, are going to endear you to fellow members.
Don't be selfish
Clubs are not public services laid on for your benefit. Admittedly chess often seems to be organised on the assumption that it is the most important thing in players lives - matches being played on several different nights of the week are bound to cut across other activities. In reality some of these other activities will take precedence and you will be unavailable for a match. But is it really unreasonable to suggest that once or twice a year you give up your weekly drinking session to play for your club?
Moreover if you are unavailable for a match for which you might expect to be selected tell your captain as soon as you find out. Don't wait until the captain starts checking a few days before the match. As Newcastle B's captain I used 6 reserves in 14 matches last year (2008/9). A few people may regard that as a disappointingly large number, though I suspect that many experienced captains would say I have been lucky. However what really made it easy for me was that I was always given plenty of notice of unavailability. Consequently I never found myself ringing around desparately seeking someone available at short notice.
It is understandable that work and family commitments, particularly in the case of young families, make it desirable for some to arrive at the last moment and leave on completion of their game. If this is you please at least reset the pieces before leaving! And if outside pressures ease later in your life, a little help at either end of the match putting sets out/away goes a long way to convincing people that you are not a freeloader.
Most players will at some stage find themselves approached by the captain of another team searching for a substitute. Even if you have to say no, please be polite no matter how inconvenient or insulting you find the request. Presumably at least part of your club wishes that person to continue as captain.
Do something
A club will only exist if at least some people are willing to put themselves out to make it so.
Hopefully your club will not have reached 'use it or lose it' status, but do not be surprised if internal events and informal club nights disappear if they are not supported. Don't be the person who turns up to the AGM to complain that on the one non-match night in the year that they condescended to turn up there was no-one to play against.
Amongst the most helpful things you can do are a) become a captain and b) provide transport. No captain equals no team is certainly true, whilst a requirement to rely on public transport may equate to no team also. I confess to finding the mindset that a person would rather not play than captain a team difficult to understand, but it does seem to be a frighteningly common one. To those who find the prospect of ringing around people they barely know looking for a substitute daunting I would say 'Remember these are chess players - presumably they want to play chess'. And if a regular player with a car is willing to announce 'I'll be transport if someone else is captain' they may flush out a non-driver who believes that that status renders them unsuitable to be considered as captain.