Four things which you need to know about the construction "had + better + V1": 1. 'Would better + V1' does not exist in modern English. The only correct form is 'had better'. In the phrase 'they'd better see him now', the 'd' is a contraction of 'had'. It can never be 'would'. 2. You said "I do think 'would better' stands for to prefer". No, you are not correct. There are two mistakes here: - 'Would better' does not exist. - 'd better' does not mean 'prefer'. See #3. 3. A common mistake among non-natives, particularly Russian speakers, is to try to use 'had better' to mean 'prefer'. For example, you'll often hear this incorrect use of 'd better': " I like winter sports. I enjoy skiing but I'd better go snowboarding. That's my favourite sport". This speaker has clearly misunderstood the meaning of 'had better', or else been incorrectly taught'. The correct way to say this would be 'I'd rather go snowboarding'. The only meaning of "I'd better (do this)" is 'I really should do this'. This means that there will be negative consequences if I don't do it. For example, "I'd better go now" means 'I need to go now' (because if I don't go now, I'll miss my bus and I'll be late for work, for example). It can never mean 'prefer'. 4. Don't believe any native speakers who tell you that it's correct to say "You better" without the 'd'. This is an informal, non-standard form which is not generally used by educated native speakers. You will hear this, but it is not considered to be correct in standard English.

It is "they had better" it's a bit of past subjunctive sneaking in. It implies that if they don't see him now they might not ever be able to see him, because he can't last much longer. As Steven said would + be + better is common; it's used conditionally. - It would be better if you went. You could say it means "prefer", in this case (the preference would be that you left) The only use of would + better I can think of is: - I just wish he would better himself. It sounds a little strange, but I think it's correct. It means I would like it if he could improve himself, or do better than he has done before. It sounds quite archaic to me.

There is a way of saying this using 'would'. For example: "That's why if they don't want to miss him they would be better off seeing him now rather than later".

I do think "would better" stands for to prefer.Am I correct?