I read somewhere that the cells in our human bodies get replaced by brand new cells about every eight years. Blood cells. Stem cells. Brain cells. They keep getting worn out and dying at different rates. We become essentially new people every eight to ten years as almost every single cell in our body replaces itself with a new cell.

So my daughter, who died almost eight years ago, if she had lived would be a wholly regenerated being since the last time I saw her. I am grieving for someone I wouldn’t even know anymore, not the girl who smelled like mustard and lily-of-the-valley, whose feet I rubbed regularly even as the cells of her red-painted toes were shedding and renewing themselves right under my fingertips.

This occurred to me in the middle of the construction going on in my kitchen to replace major parts: the structural framing decayed by two decades of water damage (human bones get replaced once a decade), deteriorated insulation (human fat cells replenish themselves every eight years), and the cracked concrete countertops now being jack-hammered into smithereens (skin cells last two to three weeks before quietly sloughing off at a rate of a million cells a day).

Everything is changing. Sometimes aggressively, sometimes barely noticeably. Life is nothing like it used to be. Regeneration of cells aside, I, myself, am not who I used to be. My daughter would hardly recognize me. The mother she knew has been replaced cell by cell. And maybe I’m not happier these days, but every cell of me has a greater awareness and capacity for happiness than ever before.

What doesn’t change? Have you, yourself, changed for the better or—