In my experience, there are a few key factors that tend to affect a POT's decision to use non-condom birth control on a regular, ongoing basis.
1. Costs vs budget
2. Religious and/or cultural taboos
3. Ease of access
4. Personal/women's health awareness
5. Have some level of intolerance for hormonal treatments like BC Pills, Depo Shots, IUD's etc.
This tends to mean, at least in my experience, that younger POT's, POT's who are Catholic or Hispanic (especially from poorer Latin America backgrounds), can't afford or do not have health insurance, and who have not had or seen serious health issues will all be less likely to be on BC.
In general, I have found that a POT who has been sexually active for a long time (say 2+ years) and who definitely does not want a child, will be on BC. That means older POT's (say 25+), who come from middle-class or higher families will be more likely to be on BC. Still, I have had perhaps a dozen SB's over the last 10 years who could not deal with the hormonal changes to their bodies. With them, I used other methods like the sponge (no longer made after covid), spermicidal creams, Female Condoms (you now need a prescription), etc. All of these are less effective than BC pills or the Depo Shot, and less effective than a male condom. But I was able to use some of these with success.
It's always a good idea to discuss before you go bare (along with talking through tests) about her BC status. It's also critically important, but much more difficult to assess what she might do if she gets pregnant. Prior to my vasectomy, I have offered to pay for her BC more than once. That usually leads her to do enough research to find out she can get free BC from Planned Parenthood and other sources.
Here's some proactive steps you can (ok MUST) take if you have not had a vasectomy and do not want a baby.
1. Beware the SB who may try to set a pregnancy trap. If she's already a single mother with 1 or more kids, says she would never get an abortion, and still has not decided to get on BC, time to bail. She's made it clear that when (not if) you get her pregnant you will be on the hook for 18+ years of support.
2. Even if she says she has had one or more abortions, that does not mean she will with your kid. You have to make an objective assessment if you can trust her when needed.
3. Relying on the pull-out strategy is a myth. By the time you are ready to cum, you have already dropped more sperm from your pre-cum drops than your full ejaculate will contain.
What can you do? Use the Level 1 Hail Mary first:
Buy several doses of generic Plan B on Amazon and keep them in your go-bag. If the condom breaks, or you did not pull out prior to pre-cum, have her take the pill ASAP - while you are still with her. Don't give her the dose and trust her to take it tomorrow. I'll add a link in Amazon. Note: I'm not sure if post-Dobbs SCOTUS decision and states have banned the sale of Plan B by online or retail sales. I know it's legal in California. You will need to check for yourself.)
If the Level 1 Hail Mary does not work, it's time for the Level 2 Hail Mary:
This one is, frankly, mean and manipulative.
But the alternative is to start writing checks. Start talking to her about your desire for a meaningful and permanent relationship. That may mean telling her you will leave your Wife, SO, whatever. That may mean telling her you want to marry her - at some point and have her fully share in your life (and assets) as an equal partner. Just make her believe it without ever documenting it. Then explain that the timing needed to achieve your future can't include a baby right now. It's just too soon and won't work. BUT, if she waits until you (divorce, break up, move, get a better job, whatever), you can start an amazing, loving family together. Offer to pay for all expenses, offer to drive her to the facility. Once it's done, take her home, give her a $25 Starbucks card, then leave and dump her by text just before you block her. I have never had to do this. And it has a very low percentage chance of success. But what else can you do?
Life is good
The Cat