Tested a 24-hour follow-up rule for two weeks

I have four retainer enquiries sitting in my inbox from March that I never chased past the first call, so the problem is not leads. For two weeks I set a reminder 24 hours after every first call and sent one plain message, no deck attached. Two of seven replied, one booked a second call. Still not sure the rule is what did it — my head was in it because I was counting.