probably as soon as you can... i got mine from a rescue so i didn't but i did a couple of months later

hope this helps

guinea pig owner

As soon as possible. If you are getting the guinea pig from a pet store, the most common illness they may have is an upper respiratory infection. It's good to have the vet check and make sure this disease is not present, so you can catch it early. If it's from a pet shop, could also be pregnant, mis-sexed, or carrying parasites. Ask them to double check the sex of your pig, and if it's a female, ask if it's possible to tell if it's pregnant. They can do an ultrasound easily on guinea pigs, but make sure you know how much this will cost, and if they have the equipment for that. pets question and answers,www.5d2d.com

Even if it's adopted from a shelter/rescue, still a good idea to have it checked out. Being transferred from the shelter/rescue to the home could harbor disease to your guinea pig.

As soon as you have time. Personally I didnt take mine but I guess that just makes me a bad mommy :/ I take them when neccessary