Summarize this article in one sentence.
Don’t wait for a problem to happen to bring your guinea pig to a specialist. These tiny animals require regular check-ups to detect potential health issues.  Most veterinarians will take care of your pet but only a few specialise in guinea pigs. Look for an exotic vet that treats rodents online or in your phone book. Bring your guinea pig for a regular check-up at least twice a year. Your veterinarian will probably recommend to neuter your male guinea pig during the first visit. This might cost a bit of money but will make your guinea pig quieter and happier in an enclosed environment.  The veterinarian will also treat your guinea pig for external and internal parasites such as worms. Older guinea pigs sometimes have feet wounds. If this happens, see a veterinary surgeon and get softer bedding or spread out a soft cloth at the bottom of the cage. Observe your guinea pigs actions. If anything seems wrong, don't take too long to act. A small infection can be lethal.  Don’t forget to cut the nails of your guinea pigs as they might be a cause of injury. Remember to be gentle. Don't give them medicine unless prescribed by a veterinarian. You might kill your guinea pig. If you notice crusty or swollen eyes, dandruff, inflamed ears or nose or irregular breathing, call immediately your veterinarian. You should also bring your guinea pig if it’s behaving erratically or if you notice anything uncommon.  Check their front teeth. Only veterinarians should take care of overgrown teeth. Their life expectancy can vary a lot. They can live between four and eight years. If you notice something unusual, separate your guinea pig immediately. You don’t want to spread a contagious disease. Weight your animals regularly to monitor their health. This will tell you if they are well and if you are feeding them enough or too much. An adult guinea pig should weight around 700 to 1200 grams. If your animal smells bad, go to the veterinarian. Guinea pigs are clean animals and shouldn’t be washed, except if they are really dirty.

Summary:
Find a veterinarian. Constantly check for injuries. Be on the look-out for worrying symptoms.