You are feeling the pain - your site is constantly going down, estimates for completion of new features have ballooned, you’re constantly fire-fighting production issues, you can’t seem to get a straight answer as to what the problem is or know how to improve the situation
Your team don't have the skills - a junior developer/agency can get you a long way. But when things start getting serious can you be sure they've made the right decisions.
You’ve been burnt before - maybe you hired someone who turned out to know less about code than you do and your developers despised, perhaps you’ve interviewed dozens of candidates and none of them has seemed quite right, or perhaps you are sick of the delays and communication problems with the various agencies and contractors you’ve worked with.