Here's my take: I'd say take 1-2 weeks off when you first get one, and even make sure you have enough free time in the first 2-3 months. The first few months is the most important; the time you spend with your dog during these few months will really determine how good they're trained and how they behave. Not to say that you can't train them when they're older but a dog's mind is like a sponge in the earliest stage and everthing sinks in fast. If you dont train it the way you want him/her to behave, it will be much harder for you to correct her behaviour when shes older. I've had a german shepherd for 6 months now. the first 4-5 months was a ton of work cuz she was a brat, I took her to classes every week, trained her everyday, etc. Only now do things seem to be alot easier. She's a lot calmer than she used to be, i've squashed
a lot of her bad habits, and don't really need to monitor her that much anymore.
It also depends on the type of dog you're getting. if it's a small dog, this might not be much of a problem, but for big dogs it's a lot more work. I see alot of people in my neighborhood who can't control their dogs, whether they're being dragged on leashes or plain just dont listen. I feel bad for them because they simply didnt do the research or spend enough time to train them. My suggestion is going for small breed: much much easier for first timers haha. BTW I'm a first timer too and if I could go back in time I probably would have gotten a small breed instead due to the huge amount of work in the beginning. But no regrets, I love mine to death haha