I've been on Warfarin since 1991. For me, the real concern was not being at the high end of my range -- it was being at the low end. In 2012, I trusted a meter and didn't test every week, as I should have, and wound up with an INR that was actually around 1.7 or 1.8 according to the hospital that treated me for a minor TIA (they called it a stroke, for me, I was back to my 'normal' in a couple weeks). I started a thread shortly after getting back from the hospital, and was searching for the most accurate meter -- you'll find that thread here.
I personally worry about advice to keep INR between 2.0 and 3.0, because shooting for 2.0 with a meter that reports higher than actual INR can mean that your INR is BELOW 2.0. I am personally a lot more comfortable with an INR reported by my meter that is 2.5 or above.
To make a long story short, I found two meters to be the most accurate (for me) -- the Coag-Sense reported INR a bit lower than the labs -- so if it tells me that my INR is around 2.5, I am comfortable that it is keeping me out of danger range. The other meter that I found to be trustworthy (for me) was the CoaguChek XS -- it sometimes reported just slightly higher than labs.
Warfarin is not to be feared. Proper management, regular testing, and infrequent, minor dosage changes should keep you safely in range. At less than a dime a pill, it's a great way to avoid stroke and to live with your mechanical valve. Many of us here remember paying a dollar or more per pill -- even then, it was a great trade-off.
I can't see how these new drugs that are being developed to replace warfarin (and, presumably, to eliminate the need for testing) will be worthwhile for most of us because we're already living healthy normal lives with warfarin and intelligent management.
