Yes it's a cliché, but like most clichés it becomes so because of it's universality and truth.
I know that I have felt at my greatest ease not when I have more but when I have less.
And by less I don't mean just things. But less worry and less responsibility for the unimportant.
I guess the strange dichotomy of the modern world is that we strive (and stress) to free ourselves from stress. We attempt to release 'things' that have a hold over us to reduce stress on the one hand, and yet with the other we accumulate more and more 'things' that compel us to do something with them.
We accumulate in the vain attempt to provide a level of happiness that material things alone can never provide. If we continue to be extrinsically motivated (by things, and by the expectations of others) that happiness we seek can never be found, and can never be lasting.
Certain of life's things we can have in abundance of course, and those by and large are intangible, and are what I consider to be the stuff that life's made of! Love, laughter, and moments of joyous experiences.
What we have should be determined by these factors. Otherwise we are simply putting the cart before the horse.
We should ask ourselves: 'Am I trying to achieve happiness by possessing this 'thing' (or person...)?...or does this thing help me to have great experiences in my life of wonder and joy?
The difference whilst subtle is enormous.
There is only one thing in life that we can never have too much of...and that is unconditional love.