Dealing with a Deadbeat, Irresponsible Ex

I originally posted this in a moms community, specifically for the members of a single moms group. I decided to post it here as well, as I got a lot of good feedback on it, and I can't think of what else to write!
It's taken 4 years of good and bad experiences, 2 years of therapy (for both me and my girls) and a myriad of other conversations, trials, tribs, blah blah blah to get where I am with this. Not that I'm perfect at it, but these are the things that are most important to keep in mind.
1) Child support and visitation are, for the most part, exclusive of each other. Check your local laws, but usually, you cannot withhold visitation for lack of child support.
2) If it all possible, get sole legal custody. This means that you do not have to get the deadbeat's permission on school forms, out-of-state travel, and a myriad of other things that may come up.
3) If you're concerned about alcohol or drug abuse, or any other problems that might make the deadbeat an unfit parent as well, set up conditional visitation. For instance, my visitation only applies if my ex has (a) a driver's license, (b) established residence in the same county as us, and (c) random drug tests at my discretion but his cost. So far, he hasn't made it past (a) yet, so he is not entitled to any visitation whatsoever.
4) I do allow visitation under proper supervision. Now that he's living with his parents and near the rest of his brothers and sisters (and their children), I do allow about 2 prolonged visits with them a year. (This also gives me a break from being "Mommy" for a few days.) However, they must arrange and pay for flights or other forms of transportation. The girls are also old enough to understand that their dad does not have a valid driver's license, and therefore, is unable to drive them anywhere. The girls have a great time with their family, and I feel safe about their well-being.
5) The major question that you should ask yourself is whether or not your child will be safe, or what can be done to make the situation safe? If nothing can be done to make the visitation safe, then you need to say no.
If your deadbeat tries to make you feel guilty for keeping the child away from their father, try to keep in mind, is this person really a father or not? Can he live up to the responsibility that the word "father" implies? If you have any doubts whatsoever, then you are under the obligation as the mom, to NOT let your child/ren be alone with him. If it's just your anger or hurt that's holding you back, then you need to let it go. Every child does deserve as much love and support as they can get.
Of course, it's important not to badmouth your ex (however bad he may be) to your child/ren, but it is acceptable to tell them the amount of truth that they can handle at their age. For instance, at this point, my daughters do know that their dad has not lived up to the "rules" in place by the court in order to have regular visitation (i.e., every other weekend, like some of their friends). They know he doesn't have a driver's license and does not live in the same county as us. They do not know the last condition, but it's only a matter of time before it becomes appropriate for me to share that with them. Throughout certain events, they have learned that their dad isn't very responsible, and they are aware that he does not give me money on a regular basis.
They are also learning, just through our daily existence, that I am the one that's here for them. I'm the one who has gone to every school event, every Halloween parade, signed all their report cards, gone to all of the parent teacher conferences, and taken them to every doctor's appointment. As the years go by, while they still love their father, and miss him, they do not rely on him the way that they rely on me.
As hard as it is, as frustrating as it can be, the rewards are there. They're there in the tears you wipe, the hugs and kisses you give, and the oohs and aahs you exclaim over their latest drawing. The truth always outs. And being the responsible parent always pays off in the end!