Make it clear up front that you will charge for maintenance work, and if they can't afford it then it's a sad world, but you'll have to move on. You can try be nice and include free bugfixes for issues that are your fault -- this is nearly always a bad idea. You'll end up some some client that will be incredibly insistent that new features are actually bugfixes and all kinds of problems.
Always charge. People will respect you more, and any work you do for them for free will be abused. This is simple human nature - when you give away work for free, all you are creating immense confusion in the recipient. "Why did I get this for free? What's wrong with it? Is this guy so desperate?" This line of reasoning will quickly blossom in your clients mind, and before long your client will expect you to get up at 3am in the morning to add in some new feature he just dreamed up. When you refuse, his expectations of you are shattered and you will be remembered negatively - even when you just gave him free work!
Always charge. The less you need the work, the more your charge. The less you want to do the work, the more you charge. The more difficult the work is, the more you charge. No freebies, unless you make the reason extremely clear up front to prevent any confusion.
Always charge. People will respect you more, and any work you do for them for free will be abused. This is simple human nature - when you give away work for free, all you are creating immense confusion in the recipient. "Why did I get this for free? What's wrong with it? Is this guy so desperate?" This line of reasoning will quickly blossom in your clients mind, and before long your client will expect you to get up at 3am in the morning to add in some new feature he just dreamed up. When you refuse, his expectations of you are shattered and you will be remembered negatively - even when you just gave him free work!
Always charge. The less you need the work, the more your charge. The less you want to do the work, the more you charge. The more difficult the work is, the more you charge. No freebies, unless you make the reason extremely clear up front to prevent any confusion.