you'd is you would when followed by a bare infinitive: you'd go, you'd see, you'd know = you would go, you would see, you would know. you'd is you had when followed by a past participle: you'd gone, you'd seen, you'd known = you had gone, you had seen, you had known. you'd never means you did .
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.