ive been meaning to do this for probably six months and kept putting it off because i knew it would be annoying to set up properly. but one of our clients (the difficult one, always the difficult one) kept asking whether we should shift budget from cold email to linkedin DMs and i didnt have real numbers to give him. so we ran the test.
here are the raw numbers across 4 client campaigns, 11 weeks, jan through mid march 2025:
LINKEDIN DMs (via Dripify + Sales Navigator) total messages sent: 2,840 connection accept rate: 31.2% reply rate on accepted connections: 18.7% positive reply rate (actually interested): 6.1% meetings booked: 23 cost per meeting: roughly $189 tool cost: Dripify $79/mo + Sales Navigator $99/mo + my VA doing 2hrs/day of profile prep and follow up
COLD EMAIL (via Smartlead) total emails sent: 14,200 reply rate: 3.4% positive reply rate: 1.1% bounce rate: 1.3% meetings booked: 41 cost per meeting: roughly $112 tool cost: Smartlead $94/mo + Maildoso for inboxes ~$130/mo + Prospeo for enrichment $99/mo + MillionVerifier ~$30/mo
ok so the obvious takeaway is cold email wins on volume and cost per meeting. 41 meetings vs 23 meetings and cheaper per meeting. but... its more complicated than that and im going to try to explain why.
first the linkedin side. that 6.1% positive reply rate is honestly really good for what we were doing. these were all professional services targets, mostly founders and partners at firms between 10 and 200 people. accounting firms, law firms, one IT consulting client. the quality of those 23 meetings was noticeably higher than the email meetings. our difficult client (the IT consulting guy who emails me at 11pm with "quick thoughts") actually closed 3 of his 7 linkedin meetings which is a 43% close rate. his close rate on email meetings was closer to 18%. so the meetings are more expensive to generate but they convert better because theres already a relationship established through the linkedin connection.
the problem with linkedin though is it just doesnt scale. 2,840 messages across 4 clients over 11 weeks is not alot. we were running maybe 250-300 connection requests per week across all accounts and being careful not to trigger linkedins limits. dripify handled the automation fine but you still need someone manually reviewing profiles and personalizing the first line. my VA spent probably 40 hours total on linkedin stuff during the test which adds real cost that isnt in the tool budget.
also linkedin has this annoying thing where your results are completely tied to how good the profile looks. we spent a full week before the test optimizing all 4 client profiles, getting decent headshots, rewriting the headlines and about sections. one client had a profile that looked like it hadnt been touched since 2019 and his accept rate was 22% vs the best performer at 38%. same targeting, same message frameworks, wildly different results.
now the email side. 14,200 sends over 11 weeks is pretty modest honestly, we usually do more but i wanted to keep the volume comparable-ish in terms of effort. the 3.4% reply rate is about average for what we see across professional services. nothing spectacular. the 1.3% bounce rate is where i want to talk about something though.
when we started the test our bounce rate was sitting around 4.2% which is not great. we were using a different enrichment setup and basically getting too many stale emails. switched to Prospeo for the enrichment step about 3 weeks into the test and our bounce rate dropped to under 1.5% which made a real difference in deliverability across the board. the bulk processing on Prospeo is a little slow when you upload big lists, like 2000+ contacts can take a while, but the email accuracy is solid enough that we dropped our old enrichment tool entirely.
the email infrastructure matters alot too obviously. we ran 12 inboxes through Maildoso, warmed them up for 3 weeks before the test started using Smartlead's built in warmup. each inbox sending around 25-30 emails per day. nothing aggressive. all custom tracking domains, SPF DKIM DMARC all set up properly. this is table stakes stuff but i mention it because the linkedin side doesnt have any of this overhead. you just... send messages from your profile.
wait i should mention the content difference too. our linkedin messages were short. like 40-60 words max for the first touch. very conversational, always referenced something specific about the person or their company. our cold emails were longer, 80-120 words, more structured with a clear CTA. we tested both personalized and semi-personalized on the email side and personalized outperformed by about 0.8% on reply rate which tracks with everything ive seen before.
the thing that surprised me was how the two channels interacted. for one client we ran both linkedin and email to the same target list (different contacts at the same companies) and the brand recognition effect was noticeable. people who got a linkedin connection request AND a cold email were more likely to respond to the email. we didnt measure this rigorously but anecdotally it came up in maybe 4 or 5 replies where people said something like "i saw your name on linkedin too". i had always assumed multichannel was just marketing fluff that agencies use to justify higher retainers but there might actually be something to it.
for our setup the total monthly cost breakdown looks something like: Smartlead $94, Maildoso ~$130, Prospeo $99, MillionVerifier $30ish, Dripify $79, Sales Navigator $99, plus VA time which runs us about $800/mo for 20hrs/week. thats roughly $1,330/mo in tools and labor for the whole operation across both channels. not cheap but when youre booking 60+ meetings a month across 4 clients the math works.
the winner depends entirely on what you optimize for. if its volume and cost per meeting, email wins and its not close. if its meeting quality and close rate, linkedin is better but you cant scale it the same way. if i had to pick one channel for a professional services client with a decent budget id still say email first, linkedin second as a supplement.
our difficult client ended up wanting both which means more work for us but also a higher retainer so i cant really complain. well i can complain about the 11pm emails but thats a seperate issue.
anyway thats basically what 11 weeks of data showed us. take it with a grain of salt because this is just 4 clients in professional services, not a massive sample. different verticals will probably look completely different