Dollar-cost averaging is the practice of investing the same dollar amount on a regular schedule regardless of price. It smooths out entry price and removes the pressure to time markets.
On average, lump-sum wins about two-thirds of the time because markets rise most years. DCA wins on psychology — investors are more likely to stay in.
Monthly is standard and matches most paycheques. Weekly and biweekly work fine; daily adds friction without meaningful benefit.