Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.
In the beginning, though, you do need to have it monitored more frequently because it's very common for INR to swing wildly as your body adjusts to the medication and until your doc dials into the right dosage for you. I would think after a while it will be 1-2 weeks until they see some real consistency and then it will eventually be every month.
Also, as you become more active and get back into your life, that can make your INR unstable. Things that involve activity, diet consistency, etc can affect your INR.
Before I had the home tester, though, I only did once a month. That's pretty standard once you get stable. However, when you're new or have something going on (like taking antibiotics, which always messes with my INR), it is very common to check every 3-4 days or so until they start to see some consistency with numbers.
I assume that they are trying to keep you in the 2.0 to 3.0 range? Sounds like you're getting closer!