OpenPhone vs KrispCall for Agency Client Tracking Numbers

Most agencies set up a dedicated call tracking number when a client engagement starts, route it into their ad campaigns, and then move on to the next thing once the campaign launches. The number rarely gets revisited unless something breaks. When the client eventually leaves, that number often keeps existing on the agency's bill, sometimes still listed in an old campaign somewhere, quietly costing money for a client who stopped calling months ago.

If your agency regularly spins up a number for a two-month campaign and expects to retire it right after, KrispCall's lower per-number cost and quick provisioning across markets make that churn cheap. An agency running twenty small campaigns at once doesn't want to pay a premium per-seat rate on numbers that exist for a season and then get thrown away.

For an agency with a smaller number of long-running retainer clients, the picture reverses. OpenPhone keeps the full call and text history attached to the client's thread, so when a new account manager takes over a retainer, they can see what was already discussed instead of starting cold. That continuity is worth more than saving a few dollars a month on a number you'll be running for years, not months.

• List every active tracking number and match it to a current, paying client.
• Flag any number tied to a client who churned more than sixty days ago.
• Retire or reassign flagged numbers rather than letting them sit active and unused.
• Check that each active number is still correctly wired into that client's current ad campaigns, not an old one that's already been paused.

Say your agency runs forty active client engagements; a quarterly audit that finds even five stale numbers still billing is real, recoverable cost, not a rounding error.

Agencies lose the most value not when a client leaves, but when an account manager does. If the departing manager's calls with that client lived only on their personal line or a number nobody else could see, the replacement manager starts the relationship from zero, asking the client to re-explain history the agency should already have on file. Whichever platform you choose, make sure client-facing numbers belong to the account, not the person currently managing it.

New client acquisition for a services business runs at a median CAC ratio of about 2x new revenue¹, so a client lost to a bad handoff experience is not a minor inconvenience, it's roughly two dollars of acquisition spend gone for every dollar of monthly retainer that client was worth. Weigh that against the relatively small cost of paying for shared numbers on your longest-running accounts.

Say your agency spends heavily on outbound content and referrals to land a new logo; a client who churns because a handoff felt disorganized is undoing marketing work the agency already paid for, not just losing one month's invoice.

Add tracking number setup to the same checklist as contract signing and campaign kickoff, rather than treating it as something the account manager sorts out whenever they get to it. On KrispCall, that means provisioning a local number the moment a campaign's target market is confirmed. On OpenPhone, it means creating the shared thread and adding every team member who might need to answer that client's calls, not just the primary account manager, before the first call ever comes in.

Do the same in reverse when a client leaves: put number retirement on the offboarding checklist, right next to canceling their ad accounts and archiving their campaign files, so it happens the same week rather than whenever someone eventually notices the line is still active. A checklist that lives in the project management tool your team already uses works better than a written policy nobody actually remembers to check on a busy Monday.