I know, provocative title. But I ran some numbers.

I analyzed the nominal closing values of the S&P 500 index back to Jan 2, 1957. Of the 14190 daily closes,

853 (6.0%) were a record high.

2289 (16.1%) were within 1% of the current record

5774 (40.7%) were within 5% of the current record.

$1000 invested on an average day turned out to be worth $1583 after 5 years (annualized return of 9.6%)

$1000 invested on an average day in which the index was at a record high turned out to be $1601 5 years later (9.9%)

$1000 invested on an average day in which the index was at least 20% below the current record, turned out to be worth $1480 after 5 years (8.2%).

I guess what I'm saying is market timing doesn't work.