- We had better get out of here before they see us.
Is "had" absolutely necessary here? Will the sentence be correct without "had":
- We better get out of here before they see us.
There is a difference between descriptive grammar and prescriptive grammar. Descriptive grammar tells you how English is used. Prescriptive grammar tells you how most well-educated people believe it should be used.
"We better" is wrong according to prescriptive grammar because the sentence doesn't have a verb.
"We better" is fine according to descriptive grammar because many native speakers say it.
So if you are trying to pass a TOEFL, write an academic essay or research paper, or do anything else where you want to appear to be well-educated, you had better include the "had" in your sentence.
By Googling it, I find support: https://ruthlesseditor.com/you-better-vs-you-had-better/
When you are suggesting that someone should or ought to do something, the correct was to say it is had better
For people speaking carefully, the "d" is there, but it gets "swallowed" in fast speech.
Make sure you keep it in your writing.