What I have learn is that abstaining from sex for a few days before ovulation helped build up a man’s sperm count thus improving the chances of conceiving. Quite contradicting and confusing.
Maybe daily sex only applies to couple with relatively normal semen parameters. So they should have sex daily for up to a week before the ovulation date in order to conceive.
There are a lot of disputes about the frequency but for me, I firmly believe that it depends on the partner and their condition. If they can sustain doing it daily and without affecting the quality and the volume of the semen, then much better. The chance of conceiving is excellent.