Lately, I've had two very similar experiences.
The first one was that there was a small vanity publisher who looked for an illustrator to do some work for a book cover. Since it looked like my kind of stuff, I emailed them and they replied that they wanted to see a sample drawing in advance that looked like (insert some description here). They would request those sample drawings from the applying artists and choose the one that suits them most, to do the job.
I turned that down - why would I do work in advance without getting anything for it, not even being sure that I'd get the job? Plus, they can estimate my skills when they look at my gallery.
Some days later, I applied for another freelance job. The project maker chose some artists, me among them, and sent them all a line drawing that they were to color if they wanted the job. The best one would get the job. Again, I decided not to do that. I have many colored drawings of that same kind in my gallery already... didn't the project maker look at the samples of my work I sent them? They should be able to look at my work and decide whether I'm good enough for the job or not.
Please tell me that it is not common practice to do work in advance for nothing I'm kinda insecure now.
Project tests are very common when applying for a full time job. When it's freelance stuff I'd tend to shy away from this kind of spec work. I think people in the creative field get the shaft in this sense, people assume that you do this for fun, and don't consider the value of your time. It's not like you'd hand an accountant your W2's and receipts and tell him to do your taxes first before you decide to whether or not you'll pay them.
check out http://www.no-spec.com/ for more info on the NO! SPEC movement.
Same as Proj235 here. I have done my share of art tests to get salaried work but I'm against doing it for freelance, especially if they are asking you t do something directly related to the work at hand that they ultimately could use behind your back and not pay for. It's one thing for someone who, for exemple, places an ad for a map artist to say that they like your art but they'd like to see actual maps (and then if you don't have any you can choose to whip one out real fast) and it's a completely different thing to ask for a 600x800px map of a medieval village with a church next to the forge with pine trees to the north.
It is common practice that a great many "employers" ask for spec work. It's also common practice that a great many others do not. I run into the former way more than I do the latter.
I think your instincts are good, when you turn down doing any spec work. It should be the rarest of days when you feel justified to do spec work for someone. You shouldn't be insecure about yourself or your work, though. You just need to gear yourself up to market yourself in such a way where you can make the odds go in your favor.
You're going to have to deal with a certain percentage of these annoying "employers" who require spec work, or some other kind of bad practice. Unfortunately you're the one who has to somehow increase your marketing scope wide enough to stay ahead of the curve. The more you blanket the right places with your resume (even the places that you wouldn't normally apply to), the better your chances are to get the few(er?) proper employers to then offer you jobs. I hope you're doing something along these lines.
You just have to play the odds to your favor. What really sucks is that entails an incredibly huge amount of extra time on your part. I hate it when sometimes it feels that the full-time job I'm working at is trying to find, well... full-time work.
But that's what we do.