I can answer yes to all of the above.  To be honest, there is no easy answer.  I feel the best approach is to require a deposit.  We have a few customers we really don't have a choice but to give terms.  I think it's just part of being in business.  It's our required learning curve blessing.  You have to keep a positive attitude.  Know that you're doing everything right.  You will have some losses along the way but hopefully it's minimal.  What I do know is the first 13 years in business I could probably write 5 books on what not to do.  I'm constantly working to improve myself and my companies processes and relationships.  Good luck!  Stay Positive!  Make the most of each day because you're not promised tomorrow!