When deciding how much notice to give your employer, consider your contract, company policy, and the amount of time it would take to train a replacement. You should also balance your needs with those of your employer. Look out for more cursory but easily overlooked things as well - these could be whether there is a non-compete clause in the contract, and the current job market.
Below are links to more short & concise blog posts. Many readers find them thematically and informationally useful.
- How to answer what is your notice period during a job interview (suggested response)
- Consequences of not giving proper notice
- What does a notice period mean (definition and a quick explanation)