Answer:
What measures out time until in time all is smashed to it?
Die without me, never thank me. Walk right through me, never feel me. Always watching, never speaking. Always lurking, never seen.
Three little letters, a paradox to some. The worse that it is, the better it becomes.
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
It doesn't live within a house, nor does it live without. Most will use it when they come in, and again when they go out.
If lightning strikes an orchestra who is the one most likely to get hit?