Finally negotiated instead of just saying thank you and taking the first number

Got an offer, said I needed a couple days, then actually looked up comp data instead of guessing. Went back with a specific number and the reasoning behind it instead of just "can you do more." Recruiter came back with an 8% bump and an extra week of PTO within a day. Not a huge ask apparently, just nobody had asked before. Wish I'd done this on my last three offers instead of assuming the first number was final.