How do you guys make sure you get paid?

[Lynch, Jonathan]

When I was a freelance videographer, I got burned once after giving a
guy a music video I created for him before getting full payment.

He never paid me. It was a small, simple project, and it was only $400
dollars that I got shafted out of, but I learned from that lesson. From
then on, the client got the finished product when I got the final
payment. I was nice (even apologetic) about it, but very strict about
that rule.

If you create an application for someone, and periodically e-mail an
updated version of the incomplete app to them, to make sure you are
creating exactly what they want, then how do you prevent them from just
keeping the last incomplete version, using that, and not giving final
payment?

Yes, you could always sue them, but that is such a mess.

Also, how do you ensure that they do not change their mind and decide
they don't want it at the last minute, after you have put great work
into it?

Or - are these things not really problems because they happen too rarely
to be a concern?

Cheers,

Jonathan