Companies often think a channel is maxed when it's just poorly optimised. Here's how to tell the difference:
Channel is not maxed (needs "better", not "new"): Conversion rates are below benchmarks (your 1% CTR on LinkedIn ads versus 1.5% benchmark means creative needs work). Landing page conversion is below 3% (needs optimisation). You're reaching less than 50% impression share (there's more volume available, you're just not bidding enough or targeting is too narrow). Competitors are running similar campaigns successfully (proves volume exists, you just need to compete better).
Channel is maxed (time for "new"): You're at 80%+ impression share and can't grow without dramatically higher bids. Conversion rates are at or above benchmarks (creative is optimised). CPCs are rising despite constant impression share (competition increased, you need to outbid just to maintain position). Volume has flatlined for 3+ months despite increased budget. You've tested all reasonable audience segments and creative variations.
Example: You're running Google search for competitor keywords. You're at 60% impression share, £5 CPC, 30% demo rate. Increasing bids to 80% impression share raises CPC to £8 and demo rate drops to 25% (you're reaching less qualified searchers). Is the channel maxed?
Not yet. Try "better": optimise landing page to improve demo rate from 25% back to 30% or higher. If you achieve 35% demo rate, you can afford £8 CPC and stay under target whilst reaching more volume.
Now if after optimising you still can't hit targets at higher impression share, the channel is truly maxed. Time to add a new channel.
Focus on one primary channel is smart, but you need one backup for risk management. Two specific risks:
Platform risk: Your Google Ads account gets suspended for policy violation (even if you did nothing wrong). Your LinkedIn ads account gets restricted. Your cold email domain gets blacklisted. If 100% of your leads come from one platform and that platform blocks you, your pipeline goes to zero overnight. A backup channel (even running at small scale) means you can survive whilst resolving the issue.
Market saturation risk: You dominate competitor keywords for 6 months, then three new competitors enter and bid up CPCs by 3×. Your channel becomes unprofitable overnight. If you have a backup already running (even at small scale), you can shift budget immediately rather than starting from scratch.
The solution: 80% budget and effort on primary channel, 20% on backup channel. Primary channel is optimised and scaled. Backup channel is tested and proven but not yet scaled. When primary channel hits problems, you can shift focus to backup without starting from zero.
Example: Your primary channel is Google search (competitor keywords and solution category keywords), delivering 3,000 leads/year at £100 CAC. Your backup channel is LinkedIn ads to target job titles, delivering 500 leads/year at £120 CAC. Google is 85% of volume and gets 80% of your optimisation effort. LinkedIn is maintained as a working backup.
When Google CPCs spike due to new competitors, you shift: pause Google, increase LinkedIn budget 3×, apply your optimisation skills to LinkedIn creative and landing pages, launch secondary backup (remarketing) whilst LinkedIn scales. Within a month you're back to target lead volume, now via LinkedIn instead of Google.
Don't run five channels at 20% effort each. You'll master none of them. Run one at 80% effort and one at 20% effort. This balances focus and risk.
Channel selection isn't a one-time decision. Review performance weekly and reallocate budget based on what's working.
Create a weekly tracking sheet: channel, impressions, spend, CPM, CTR, clicks, engaged visitors, leads, cost per lead, MQLs, cost per MQL. Flag channels exceeding cost targets in red. Flag channels below cost targets and with room to scale in green.
Every week: increase budget on green channels (scaling winners), decrease or pause budget on red channels (cutting losers), test improvements on yellow channels (close to target but needs optimisation). Reallocate freed budget from red channels to green channels.
The discipline: give new channels 4 weeks minimum before killing them. Week 1-2 is learning (audiences, creative, targeting). Week 3-4 is optimising. If after 4 weeks a channel is >2× your cost target with no improvement trend, kill it. If it's close to target (within 1.5×), give it another 4 weeks with focused optimisation.
Example: You test LinkedIn ads. Week 1: £150 cost per lead (target is £112). Week 2: £145 (improving). Week 3: £130 (still improving). Week 4: £115 (close to target). Continue and optimise. By week 8 you're at £105, below target, and scaling.
Compare to: Week 1: £180. Week 2: £190. Week 3: £185. Week 4: £180. No improvement trend and 60% over target. Kill it. Reallocate budget to working channels.
This weekly discipline prevents both premature killing (you quit week 1 when week 4 might have worked) and zombie channels (you keep running something for months because "maybe it'll improve" when it clearly won't).