A form comes in at 9:42 pm and gets a call back the next afternoon. A missed call goes to voicemail, and the caller rings the next company. Nobody chases the no-show.
To your client, that looks like bad leads. The blame lands on you, and it costs you the retainer, over something you never controlled.
A lead-to-close system fixes everything after the inquiry: an instant reply to every lead, follow-up until they respond, booking with reminders, and a monthly report showing your client what happened to every lead you sent. Because it carries your brand, it becomes part of your package, not another vendor your client has to manage.