There is no shortage of relationship advice available, and one of the most common phrases is: Accept your partner for who he or she is and don’t try to change him or her.

While you may be able to make minor tweaks — like getting your significant other to wear dress pants instead of athletic shorts when you go out to eat — trying to make major changes to your partner is not part of a healthy relationship. Here are 4 things you will never be able to change about your significant other — no matter how hard you try.

1. Personality

It is nearly impossible to get someone to behave exactly the way you’d like. People are who they are, and though some personality traits are due to social conditioning, there is no way to turn your partner into a “perfect” version of how you think he or she should act and be.

In fact, the propensity for change diminishes greatly once you turn 30, and we’ve known this for over 100 years. Groundbreaking Harvard University psychologist William James’ text, “The Principles of Psychology,” published in 1890, found that your personality stabilizes in adulthood. Part of the text says, per New York Magazine’s Blog Science of Us: “In most of us, by the age of thirty, the character has set like plaster, and will never soften again.” Additional research has shown that our core personality traits have a strong genetic component attached to them and remain constant throughout our lives.

2. How your partner relates to his or her family

Families, especially your partner’s parents, can be a touchy subject, and if any sort of criticism of them comes into the conversation, it’s like walking into a mine field: an explosion can happen at any time. Karl Pillemer, Ph.D., a professor of human development at Cornell University, tells the Huffington Post, “[P]eople’s feelings about their own families are deeply ingrained, and they are not likely to alter significantly after you tie the knot.” He adds that, “[y]ou can come to compromise, but if your spouse and your family don’t get along, pressing for change is not likely to work. Instead, I’d tell you to give your S.O. a free pass to avoid unnecessary get-togethers. Family togetherness is nice, but not at the expense of your relationship with your partner.”

3. Hobbies

Relationship researchers have long believed that couples who take up similar hobbies or active pursuits together are much happier because these shared experiences bring novelty and excitement to the relationship. That being said, it’s important for partners to have separate hobbies and interests that add to their overall happiness. Asking a partner to change or stop their routine hobbies will only cause contempt and set the relationship on an unfavorable course.

4. Religious beliefs Religious beliefs are something that are ingrained in you, and often these beliefs have been passed down in your family. While it’s not completely unheard of for a person to believe less in their religion — depending upon their age demographic — or even convert for their partner, if your significant other is deeply religious it can be problematic in an interfaith relationship, Samantha Rodman licensed psychologist and dating coach tells the Huffington Post.

Rodman adds that most problems for couples, in regards to religion, don’t arise until later in the relationship or until they decide to have children.“People who were raised going to religious services frequently will often want to resume this practice when they have their own children, even if they didn’t attend services as a younger adult,” she said.

“On the flip side, if your partner is an atheist and agnostic, it’s unlikely they’ll become devout believers just by virtue of being with someone with faith.” Just remember that religion is one of the many traits that makes your partner who he or she is, and it’s unfair to ever expect a change.