If you don't focus on repeat business you're not building a real business. Spend the time it would have taken to get a new repeat customer. Focusing on cash in hand is short sighted and will mean your mindset won't be set for growth, therefore it's unlikely to happen.
Good post, well said. Don't want to go too deep into this, but I heard a clever bloke once say that attitude determines your altitude in any business. Running after every job is not for some, as some posts have said on here. One off's are for when you have time and the price is right, but I do well without them.
If you watch what the established guys on here post about this, you'll see that when your work reaches a certain level and the income is fairly safe and very steady, you see that they pick and choose to a certain point what they do and where they work and what they charge. When you're far enough into this malarky, one off's aren't really worth the bother.
I know what the OP means and understand his point, and all the best.