Founders brief me differently for BDR/SDR hires than they do for AEs, so here's the honest breakdown of what each role actually needs.
For BDR/SDR: resilience above almost everything else, you'll hear no far more than yes, and the good ones don't take it personally. Curiosity, genuine interest in a prospect's business rather than a script. Clear, confident communication on the phone and over email. And coachability: the best SDRs I place take feedback and apply it the same day.
For AE: everything above, plus the ability to run a full sales cycle, discovery, demo, negotiation, close, without someone else steering. Comfort owning a number and being measured against it. Strong stakeholder management, because at a startup you're often selling to a founder or a committee, not a single buyer. And commercial instinct: knowing when to push and when to walk away from a bad-fit deal.
Neither path is a demotion or a promotion from the other, they're different skill sets. Plenty of the best AEs I know spent 12 to 18 months as an SDR first and use that grounding every day. If you're not sure which fits you, that's exactly what the call is for.

