Recently, I had an incident that occurred with a client which prompted this post alongside a slight change to how I do things with clients. In short, this was a situation wherein there were too many hands in the cookie jar because the client in question decided that it was pertinent to hire three or four other workers alongside me, despite our conversations about how it was better to avoid complicating things. It dawned on me, as this was occurring, that he had little to no idea of why this can be an issue, so I thought I'd talk about it here.
To start us off, think for a moment about working in a kitchen with others, as that's something we've all done. What happens when you add another person to the group working on cooking a meal? The room gets slightly more crowded with each addition of a new body. Even when doing prep work, each person needs between a foot and a foot and a half of elbow room, not counting the counter space, to say nothing of the cook, whose likely wandering around the kitchen. When you've only got 6 or 7 feet of counter space on each side of the kitchen, with an aisle that's ~3 feet across, that space gets damned crowded. You've got people running around with knives, spices, meats, veggies, hot pots, boiling water, and Gods know what else; the area quickly becomes a hazardous sight.
Magic's really not all that different. If your life is the stew and the sorcerer's the chef, its up to the chef to season the stew to provide you with what you ordered (the magical result). If I am seasoning the stew, I have a pretty good idea of what spices I need to add, and what prep work I need to do. If you start adding other chefs to the mix, soon its going to become an incomprehensible mess, as I don't have the slightest idea what the hell the chef to my right is doing to the stew. He's probably adding spices I'd never thought of with impunity, totally unaware of the fact that the meat in the stew is intentionally flavored a specific way.
To drop the metaphor and get down to brass tacks, in essence, when there are too many folks doing magical work at one time, the situation can get incredibly complicated. The fact is that every working I do changes fate ever so slightly...when I'm the only one fiddling around, I can do this with a fair deal of control. That's no longer the case when you have one other spirit worker doing work concurrently. Adding more to the mix only further complicates the problem.
That being the case, its not an issue if you hired someone to do the work prior to getting me involved, so long as they've already done their work. Its also not an issue for you to hire someone a few months after I've done the work if the case is not, Heavens forbid, resolved. But for the love of all that is holy, do not hire someone else while you're having me do the work. It'll likely become a convoluted mess and have really crappy repercussions in your life.
Granted, with that said, there's some flex to this "rule". The fact is that some magical work is incredibly touchy, and other types are really rather cut and dry, for the most part. Love work is naturally a pain, and everything's a balancing game, so that's a terrible time to add confusion to the mix. Uncrossing and blessing work, however, is very direct...its simple, and generally, there's not a heck of a lot of confusion that can be caused.
Just do bear this in mind when you're either doing work for other people or having work done for you, as I'd hate to see your result get dorked up because of impatience or indecisiveness on your part.