My employer matches per paycheck, but if you contribute the max early in the year, at the end of the year, they calculate the months you missed your match and make a lump sum contribution.
I put in a lot at the beginning of the year (25% to 40%, company max), then ramp down to single digits when my cost of living adder falls for the year to a rate that will invest until the last paycheck in December. I know they do the above, but I fear the Dec. 15th changes that could remove that action for the year. The company has a track record of making policy changes that will greatly benefit them and screw over the employees. (They changed the ESPP purchase price calculation because the bottom of the crash in 2008 coincided with the calculation dates. The policy was written extremely badly originally, but everyone assumed they would honor it since it was active up to the day the ESPP price was announced. The rollout of the new policy was completed but not announced the day of the ESPP price announcement at 4X what it should have been.)