I had a vasectomy 20 years ago (I'm now 55) and it was relatively painless and the recovery easy. Some time after the procedure I was supposed to submit a sample to make sure the procedure worked as intended and frankly, I can't remember if I ever did or not. However, my wife (at the time and still current) was very fertile and I finished inside her many times with not so much as a late period. I would do it again in a heartbeat. We're in a very strong but open marriage and I still use condoms with women other than my wife. She (currently) is monogamous.
I always ask if she has clean tests. And that I do, I get them done regularly. I also am willing to share tests so we can both see. Only a few girls have ever insisted.
Then the chat on where to shoot. Since BC can mess up some women I never demand it. But I do ask as many girls are not on it. Personally I don't like CIP so for me, it's not a huge deal to pull out. I always ask if she's willing to swallow or take a face shot. You'll be surprised at what some of them are willing to do with cum. Especially if you have a clean diet as that affects taste.
My longtime SB at the time was comfortable with going BB, as we exchanged test results regularly. But she was not on BC (said it screwed up her hormones - a common issue) and I could not finish inside her.
We used all sorts of alternative BC methods. The best I could find was the sponge. But COVID made that impossible. It turns out all the sponges were made in a factory in India (trust me, I researched the HELL out of this!) and when the pandemic hit, the factory had to close to protect the workers. Once workers were allowed to come back, the key material providers were unable to send the components to the factory. The company folded and that was it. I scoured the internet to find any remaining supply; Amazon, US and Canadian drug stores and medical supply companies, even eBay. The last box I was able to buy cost me $75 for 3 sponges (normal cost was about $12). I also used to keep a supply of Plan-B doses at home (Amazon is the cheapest - about $35-40 versus $80 at drug stores in California).
I decided to get the surgery once my health care provider opened up for elective procedures. I had to fill out forms, chat with the surgeon (who just wants to make sure you know what you are doing) and schedule the 2-hour appointment. My recovery was a bit longer than normal; about 4 weeks. But then all was good.
Now when I start with a new SB, I show her my current STD test results and my zero-sperm count results as well. I still meet new POT's who don't want to risk it, or who ask for way too much allowance, but I just move on to the next.
The obvious advantages are easy to see. But there is a side advantage as well. There will be NO pregnancy scams. Since I have been enjoying my retirement by travelling to popular mongering destinations around the world (yeah, yeah, but somebody's got to do it! 
, I am aware that many of these regions especially in SE Asia have women who will try to set up a western guy for extortion by claiming to her family and (corrupt) LE that he got her pregnant and is now trying to avoid responsibility. Well, I can whip out my test results to a local defense attorney and kill that scam quickly.
So IF you NEVER want to have kids (again), and you really want to enjoy BBFS (as I do) it's a sound strategy. Not very expensive and not very painful during or after (ask your Doc about that!). Oh and you may hear that having a vasectomy can reduce the intensity or volume of your ejaculate, I have not found that to be true. Finally, it can be reversed with another surgery. But if you really think you may want to have a kid after, you can easily freeze your sperm in advance.
Life is good
The Cat
My strategy is a bit different. My concern is more about diseases than pregnancy, although maybe I should worry more about both . My default is to always use condoms. Problem solved. But I love going BB as much as anyone, and finishing inside a girl that way is exquisite! So I have discussed the possibility of going BB with several SBs and come up with the following. We will agree to go BB only if:
1. We promise to use condoms with everyone else
2. We have exchanged clean test results
3. If either of us goes BB with anyone else, there will be immediate full disclosure, and no recriminations. We'll simple go back to using condoms until new test results are done.
4. And obviously, she has to be on birth control.
I've done this with exactly 2 SBs. The first one was a 2 1/2 year arrangement, very delightful. And during that time she told me once that she had gone BB with another guy. We went back to using condoms as per the agreement, until she dumped him and got retested.
The second one is with my current #1 SB. She has agreed to being exclusively BB with only me. And she's on BC. And I trust her enough to believe her.
I should also mention that as a young man I was told by a doctor that I have varicoceles, a very common thing. But that it would make it difficult for me to father a child since they are a major cause of male infertility. Not a sure thing like a vasectomy, but another factor I consider in assessing the risk of going BB with lovely young women.
