Same here .it often takes multiple times to unlock my IP5s. It got so bad i don't even use it anymore.
I was noticing mine was failing more often than in the past, didn't know anything about the so-called 'fade' issue where performance would degrade over time. I deleted my existing fingerprint scan profiles, set up new ones and performance is once again like it was when I first started using the phone--I guess I get a read fail once every 15 or 20 attempts and usually because my finger/thumb is in a terrible position.
Supposedly, a fix for this 'fade' issue is included with ver. 7.1.