I find it so inconsiderate when recruiters call out of the blue without scheduling. With the number of spam calls people get these days, I can’t imagine many candidates are willing to pick up unexpected calls from unknown numbers.

Even if they leave a voicemail, it just puts the onus on the candidate to continue the game of phone tag until they connect. This is especially challenging for candidates who are currently employed, which should be obvious if the recruiter already has their resume.

Just send an email. Please.