For many home-based workers, the chief advantage of the home office is that it lets them achieve a more equitable balance between work and family.  The key word here is balance.  

Once of your most difficult tasks will be to convince loved ones that you really are working.  Even the most considerate family and friends may suffer from the common misconceptions about home-based work--you're available any time and you can drop whatever you are doing.  Make it clear that you are earning your livelihood, not indulging in a hobby.

- Emily Post's The Etiquette Advantage in Business

More and more of us are working out of our homes, at least part of the time.  If you are a member of this growing community, you've almost certainly run into this conundrum: you are home, so you theoretically could do a favor like drop a forgotten lunch off at school, or run to the store, or babysit your neighbor's children for a few hours.  Maybe it's not a favor, but a well-meaning friend keeps inviting you out to socialize in the middle of the work week or a parent that calls at all hours of the workday to chat.  The flexibility you probably have when working at home means that you could do some of these things, but you know that it doesn't mean you should do them.  Doing them means having to work later to make up for the time lost or doing less-than-optimal work because you have to start and stop what you were doing.  And if you know that and so you say "no," you often get a disappointed or even distrustful look that says, "why?  I know you're home; why can't you?"  

This can be a frustrating situation, as you want to do the best for your friends and family, but you also want to do the best for yourself and your company and to have pride in the work you do.  As Emily Post's book points out, it's all about figuring out your own balance and what you can and cannot do.  You need to decide on your own boundaries first and not rely on your friends and family to understand your situation and know what to do.  For some people, this will mean keeping strict office hours, just as you would if you worked in an office.  For others, this may mean keeping your door closed during the times when you can't handle distractions, but open other times when you are available to be "at home."   Every person and every job is different, but what's important is that your scheme shows that you respect your own work time, so others should, too.

Once you've decided on your boundaries, it's important you communicate them and you stick to them.  There are lots of great ways to do this.  Some are visual: for example, if you have small children at home, you change into your "work clothes" in the morning to visually remind them when it's a work day and when it's not.  Some are verbal: for example, when you're talking about doing a favor for someone, you find polite ways to work in an appropriate give-and-take balance.  For example, "sure, I can run and pick up those pills this afternoon, but I'll have to work until dinnertime then to make up for that time.  Can you take care of making dinner tonight?"  The more you consistently reinforce these things, the lower everyone's stress will be because they (and you) will know more about what to expect.