There is no one solution to the topic of when you should start looking for work if you want or need to relocate. One of the most important items to consider is your financial situation.
Considerations for Money
Can you afford to go without a salary while still paying for health insurance and moving expenses? If you have monetary reserves, it may be better to relocate first, settle in, and then begin your job hunt. If you don't, you'll need to start seeking for work before moving.
Personal Preferences
Consider your particular situation as well. Do you know anybody in the new place who might lend you a bed or a couch? If this is the case, you may want to consider relocating first and then looking for work.
What Kind of Job Are You Looking For?
Another thing to think about is the sort of work you're searching for. It is easier and faster to be employed for lower-level employment than it is for higher-level ones. It will take longer to be recruited if you are in your mid-career or higher-level role. You should plan ahead of time and be prepared to perform a long-distance job search. Keep in mind that you may be able to negotiate a start date that allows you to relocate and settle in.