if you were the only one who made quilts from patterns all those books, magazines, and patterns would be obsolete! no one would be buying them- they would be out of business-since i doubt you buy enough of them to keep them all in business.
it's not something to stress over- if you use a pattern & give it your own (spin) use your own fabric choices- not just the exact fabrics the pattern designer used- and at times change something- a different border, anything (tweeked) you are designing/ creating your own quilt-
i make alot of my own quilts- without pattern- without graph paper- without eq anything-
i start with an idea- or an armload of scraps & just start- sometimes i will make a couple blocks i like- then decide==i'm going to turn these into a quilt & work from there- everyone has their own (techniques)
you said you've been quilting for a long time- perhaps it's time to step outside your box & learn a couple new techniques---find a couple classes to take to learn something new- start browsing books, magazines looking at scrappy quilts- or row quilts- or round robin quilts- those can give you ideas on how to create something all yours-
but don't 'sweat' using patterns- without people who do think about all the people who would be out of work.