Is a past addiction always held against a parent?

The best interests of the children don’t always fit into clean timetables. But there’s no statute of limitations on protecting your children. The Golden Rule applies here. If your behavior harms your children now, then it’s not really a “past” problem, is it? If, on the other hand, you want to dig up dirt to get back at your ex or gain more parenting time, that’s shameful. People can always change, and the law rewards that, but the basic question is “What threat does the parent pose NOW and foreseeably in the future?”