This is something that every dog owner should have at home. My dog does not like it but it is important to have. When I call my vet with what I think may be a problem. he tells me take her temperature

Pros: keeps me informed of my dogs health

Cons: none

This is something most pet owners should have in their first aid kit. This type of thermometer is nice because you don't have to worry about it breaking in a squirmy dog.

Pros: Won't break, easy on your dog

Cons: None

If you have the choice between old school mercury thermometer or this handy digital and flexible thermometer there is a clear winner, and that would be this thermometer.
Flexibility provides your pet with a bit of wiggle room.

Pros: This thermometer is a whole more comfortable for your pet.

Cons: None

Great for taking quick temperatures on animals. The flexible tip is more comfortable for them.

Pros: Causes less stress than traditional thermometers

Cons: More expensive

Each pet owner should have a thermometer like this one in their home. My dog became ill one night and it was invaluable to monitor her temperature. Knowing the range and making sure it stayed lower allowed us to wait to visit the vet the next morning. This thermometer is quick and your dog will appreciate that. Easy to read and was accurate.

Pros: accurate

Cons: nothing