I've been on Warfarin for about 19 years. I'm not sure about calcification in everyone -- I may be one of the lucky ones - but my one and only angiogram, in 2001, was clear. Perhaps if you're already predisposed to calcification, Warfarin may speed it up - perhaps not. Even with calcification, it probably still beats the alternative to not having the surgery done.
Testing costs vary-as Dick pointed out. A lot may depend on your insurance coverage, in addition to what kind of MD you're using.
For me, without insurance, I took the matter into my own hands. I bought a ProTime meter on eBay (and I've bought one for backup, and a CoaguChek S because some people liked it and I wanted to find out why). I had a doctor friend order me some ProTime test setups, and I was able to get CoaguChek PT strips on eBay without a prescription. In many cases, it's probably easiest to have a doctor buy the strips for you (and you reimburse him or her), or to have a prescription for the strips. My meters on eBay were rather inexpensive (a ProTime 3, including shipping, was about $50, I got a ProTime one - which had ONLY run 6 tests, for 99 cents, and my CoaguChek S was only $40 delivered). The strips weren't a backbreaker, either. I'm certainly not suggesting what to do -- these meters work for me, and I always feel grateful, and somewhat empowered, to be able to take my life under my own control and test when I want to (usually weekly).
As far as putting off surgery - if it were me, I'd talk to my doctor and to my significant others, and see what they advise. (My question was 'How sick to I have to be before I shoudl have my surgery?'). I'd also consider how strong my insurance - and the job that pays most of the premiums - are. In my case, I thought my job would last for another decade or two or three -- but it ended less than 9 months after my AVR. Had I waited, I may have had a hard time getting my surgery - because I wound up with lesser insurance coverage - when I needed it a lot more than when I DID get the valve job.
Lifelong Warfarin therapy (until, or unless, they come up with a different anticoagulant), and Open Heart Surgery, may not be as bad as you're expecting them to be. Delaying it won't change your need for the surgery, and may complicate recovery.
Just a few things to consider...