Generally, if my daughter (14) wants to do something like dye her hair or whatever when she's with me during summer, I tell her to get her dad's permission first. I try to be on the same page as my ex but I definitely can't control what happens when she's home with him. She lives with him in Michigan and visits me during spring and summer breaks in Colorado.

Now, once she hits an age where she's asking for something more permanent (piercings, tattoos), I'll leave that up to her dad completely, even if I believe she should do it. Since he has primary custody, I give him that courtesy. If I had my way, I'd be the ultimate say-so in her life, but for now, I bend to him to keep the peace.

Over this past summer, she wanted me to dye the underside of her hair bright blue. I got her dad on the phone, he said yes, so we did it. Now when I go to Michigan over Christmas, she wants to do pink. As long as he's ok with it, I'll do it.

It's a difficult situation. It's hard to have your values and rules disregarded because the other bioparent has a more permissive/relaxed attitude. As my stepkids hit their teens they either spent more time at their mothers house, because she lets them do most things, or simply reserved some activities for her house. When SD15, who was living with us at the time, got an illegal piercing, DH and BM agreed that BM would take her to have it removed the next weekend when SD was at her house. BM didn't take her, and lied to DH and told him she had. When DH found out and was annoyed she told him he was a prude. We've also had the mad hair colour issue.

Unfortunately really obvious inconsistencies between parents encourage the children to disrespect rules in both houses, and play one off against the other. A child that thinks that all rules can be circumnavigated is going to turn into a big problem. The best case scenario is one like RedWingsFan outlines, where the parents at least consult with each other, and the children are aware of that. Failing that you just have to pick your battles and downplay some of the stuff you wouldn't have approved, like hair colouring at the other parents house, because if you make an issue out of every little thing it just draws attention to the inconsistencies. At the end of the day hair colour is not the end of the world, honesty, attitude and schoolwork are more important battles. If you're lucky the differences in parenting values aren't too huge and you can tolerate them. I think it's probably fairly redundant to prevent the children from using the term bf in your house if they are in fact allowed to have boyfriends by their mother. It's just waving a big flag saying 'we disagree with your mother but there's nothing we can do about it'. It will just encourage the children to hide things from you.

We always handled it Our House - Our Rules ... Mom's House - Mom's rules... It helped we are custodial though I'm sure

We struggle with this daily. It is hard to instill good morals and ethics with a 50/50 custody situation. When in one house you are allowed to:

Scream if you don't get your way
Eat crap for every meal (i.e. french fries, anything deep fried and warmed up in the microwave)
NOT do your homework
Lie on your reading logs
Sleep in and be late for school

And the examples set at the other home consist of:

The man doesn't work
The woman RARELY works
Everyone lies to get government support
Smoking in the car with the kids
Smoking weed is "normal"
Calling in sick to work regularly is normal
Fighting daily with your SO is normal
Making fun of other kids is ENCOURAGED

The only thing we can do is voice how UNEXCEPTABLE these things are when the subject arises, and teach them to be better than that. I have no problem pointing out the advantages that DH and I have in life from simply having GOOD MORAL AND WORK ETHIC.