Moderately minimal.

At times I ponder upon their reluctance to buy/do something, their not-so-happening lifestyles and social circles.
I guess I've found the first clue to it - that my parents are 'moderate minimalists'.
A psychologist might say (well, guessing) that they've adopted such an attitude towards life because they did the opposite and didn't find any incentive or experienced unpleasant things while doing so.
To me, they probably enjoy life as it is now. With those few strings attached.
I'm their biggest rope metaphorically speaking and to be less desirous of all things material leading to easy contentment could be the way for them. I take on their values and attitudes but it makes me misfitting at the same time, at least I feel it that way.
But it ain't that bad usually, if the quality of the intended purchase/activity's good, it's usually green light for me.