Complex sentence: Fred Durkin is a blue-collar investigator who is often hired for mundane tasks such as surveillance; he's not prone to flashes of insight, but is reliably hard-working and stubborn about getting details right.
Split into simpler sentences: Fred Durkin is a blue-collar investigator who is often hired for mundane tasks such as surveillance. Though not prone to flashes of insight, he is reliably hard-working and stubborn about getting details right.