Sure, They're Acting Normal, But....

Eating and drinking normally, along with normal bathroom habits are always a good sign. But it's no guarantee that your pet is in optimum health.
Well pet checks on a regular basis are always encouraged. But in this economy with money being tight we are seeing pets that have had problems go on so long that immediate action is necessary, and usually expensive.
Boss Man and I have had a higher than usual number of cases of mammary gland tumors and pyometra in older unspayed female dogs. When we ask the owners why they waited until the dog is in critical condition before seeking help the answer is always "But she's been eating and drinking and acting fine, so I didn't think there was a problem"
A tumor the size of a grapefruit that is dragging the ground didn't happen yesterday. A Pyo so infectious that the smell comes into the room 10 minutes before the dog does has been brewing awhile.A small male dog with testicles swollen to the size of a tennis ball is not macho nor is it healthy. Having to call an owner and tell them that their beloved pet has metastatic cancer is hard on everyone. Which could have been avoided with a simple and relatively inexpensive sterilization surgery when they were young.
These cases are expensive and time consuming. Blood work is needed to make sure the patient can survive the surgery. X rays to check for metastasis before. Biopsies of the tumor are not cheap. And the surgery itself is touchy. While we do perform the neuter or spay at the time, there is also the extra of removing the tumor and making sure the whole tumor is excised. Some of these are so large that there is very little skin left to suture together. This means a longer and more arduous recovery time for the pet, with more possible complications than a routine sterilization.
Remember the childhood taunt: "See with your eyes, not with your hands"?  This doesn't apply to having pets. A routine examination no less than once a month will catch things before they get critical. Run your hands all over your pet. Note any lumps or bumps, and their size. You don't have to measure, just compare the size (a dime, a quarter, a softball, etc). If you find something, have it checked out. Your vet may recommend surgical removal, or monitoring the progress, depending on the type of lump and the location. It's much easier on you, your pet and your wallet to remove something the size of a quarter rather than something the size of a grapefruit.  Even if everything is normal, at least getting an exam is good preventive care.
And, if you're not breeding them or are done breeding them, get them fixed.