Assembling a band
There are two kinds of bands. One "just happens" when a bunch of like-minded players get together to make music. The other is put together to fulfill someone's musical vision. The latter kind of band is incredibly difficult to assemble; you need to find band members who are willing and able to follow your vision without trying to impose their own agenda over time.
In an ideal world you'd have your choice of band members so you can pick the "perfect fit" right from the start. In the real world -- unless you're living in an area that has more musicians than your typical Pacific NW city has Starbucks -- you have to work with a talent pool that might not meet your immediate needs. If you have a strong vision of what each member should be contributing to the band, then you can state your requirements right up front. Any member who has "potential" to grow into the band should be informed that they're being hired on a provisional basis and are expected to improve in the areas in which they are currently weak. Define some measurable objectives and make sure that the new member understands the objectives, the time frame and the consequences of not coming up to par. Make it clear that you're in charge and that your decision is final; that'll save you a lot of wrangling with players who try to weasel out by claiming that they thought they were doing exactly what you asked, yada yada... even though they didn't really put much effort into meeting the stated goals.
Does this sound hard-nosed? Sure it is. The alternative is to hang around with a bunch of guys who own instruments and think it's cool to be in a band. Not that there's anything wrong with that... And it's nice if the band develops the kind of cohesiveness that comes from camaraderie. But if you have a vision for your band, you have every right to be certain that everyone is on the same page and is working up to your standards.