Use the adjective perpetual to describe something that never ends or changes. If you're a perpetual procrastinator, your dilly-dallying ways are never going to improve.
It may be true that the only constant is change, but English nevertheless has no shortage of words to describe things that never change: everlasting, eternal, and permanent, for example — and this word, perpetual, from the Latin perpetuus, "continuous." In casual usage, though, you might hear someone say "This perpetual bad weather needs to clear." Maybe it should come as no surprise to find people using the word to describe things that are not truly everlasting — since so few things really are.