Why do you need to take your Cavy to the vet?
Veterinarians are TRAINED to treat your animals and the internet is not. Sometimes you look everything up and you think you are doing the best you can, by self-diagnosing but actually taking your pet to a professional IS doing the best you can and by the time you get there it may be too late.
Especially sad when it's something really simple to fix.
First, they will likely suggest testing that will cost money you may not want to spend. You should start saving for these unexpected costs now. Dare I suggest A PIGGY Bank? Seriously, when you have extra, store it away for these emergencies so that you have every opportunity to do the best you can for your pets. Low initial cost is deceptive. The expenses of food and bedding, not to mention health care, mean guinea pigs can become surprisingly costly pets. A cavy may live as long as 10 years, though the average is five to seven, so one must consider adopting a cavy to be a moderately long-term commitment and a financial consideration.
That said, think about what you would do for your guinea pig should an emergency arise.
Some vets may specialize in dogs and cats only and can't treat guinea pigs or hamsters. Some vets are not 24 hours or are not open on weekends. Find out if they charge extra for emergencies!
Do you provide emergency services?
Make sure your pet is on the list of animals they specialize in and they know your pet's name.
If you have multiple species in your home, you probably want to find a vet who can treat everyone.
Know your Doctor's name.
Ask "How long have you been in practice?" An established vet means that they're part of the community and need to keep a certain reputation.
They should also have fair prices and good reviews online.