It is true that sperm concentrations will drop with increasing frequency of intercourse but daily intercourse in the majority of men does not drop the count enough to reduce the added conception benefit of each act of daily intercourse (source). In fact, studies show that while it's true that sperm count may go up with abstinence, sperm vitality overall goes down. Researchers found that by ejaculating within 1 to 4 hours and 24 hours again, total motile sperm count increased over and above that of the first ejaculate (source).