Vasectomy questions

BBB
My husband is scheduled to get snipped in 4 days. Has anyone gone through it? I'm wondering if it changes anything after? Like how long he lasts, or how hard he gets?. I know the Drs say no, but we had a couple guys say that it actually did for them. 
And wondering how soon after the procedure we can have sex again? I know he has to have 20 emissions in 30 days after, so it seems like they want us to get right to it.