Starting a career in photography can be an exciting, exhilarating move. Most photographers have freedom unlike any other traditional job and can book appointments as frequently as they want. Amateur photographers, that is to say those who don't get compensated for shooting, usually do so because they enjoy the hobby. Regardless of where you stand, there will be times when you need to decline an offer for work. Here are some examples of when and why you shouldn't say yes to an offer.
When you are a professional, it's your business, even if only part time, you generate part of your income from shooting. This is an important fact that will come into play now.
Weddings that you are invited to as a guest and asked to shoot, probably a good idea to say no. I'm often asked this, even though I'm not a wedding photographer. If you invite me to your wedding, let me be a guest! I want to enjoy and remember the day, not work the event. It's OK to decline shooting friends and family weddings and events.
Holidays are important, most people enjoy spending them with friends and family. If you are offered to shoot a job on July 4th (for American's) or a wedding on New Year's Eve, think about how that will impact your personal and social life. Do you want to work that holiday for strangers or spend it with people you care about?
Spec work, short for speculation, implies shooting something that a client might want to buy. Know your rates and have them agree prior to shooting. Rarely does working on spec ever benefit the photographer.
Trade work in exchange for pay. As a photographer who offers a service, you'll often find clients who will offer you work in trade, rather than straight pay. Sometimes this isn't a bad idea, but remember that trade doesn't pay your bills.
Travel compensation is not payment for services rendered. I can't tell you how many times I've heard, If we pay for you to come to (insert fancy destination on the beach here), could you shoot our wedding? If they aren't willing to pay for your services too, it's probably a good idea to say no.
Working outside your normal area of expertise. I am not a landscape photographer, nor am I a wedding photographer. So far in 2010 I've turned down four wedding jobs because it's simply not an area I'm great at. I told one person who found me through a mutual friend that I could provide good photography, but they deserve great photography. They completely understood.
If photography is your hobby, and you do it because you love it, that should be the only reason you do it. Don't get lured in by offers that sound too good to be true or deviate from your joy of photography.
Over your head jobs should be passed on. If you are asked to shoot something that you know you can't handle, suggest they hire a professional.
When the line blurs between a fun hobby and a time exhausting job, turn the job down. Photography is a hobby, a passion, a form of expression. When it stops being fun, consider saying no.
Your goal is to become a professional shooter, so you're working towards making that happen. Don't represent yourself as one until you know the quality and expertise is on par with what clients should expect. If you are honest and upfront and decline a job that is out of your scope, you could very well get another job by the same client who respected your choice to not provide sub-par quality work.
Paid work or not, professional or amateur, time is a valuable commodity. Don't take on more jobs then you can actually do, and don't forget to factor in post processing times and commuting. I generally factor in about 30-45 minutes of post processing time for every hour of shooting time I do. There are exceptions to this, but that's my general rule of thumb. Don't take every offer because you want to satisfy every customer, friend or family member, you won't be able to.