We are traveling to California in mid September. I plan to bid on Priceline for the nights we will be in Monterey and SF. I have never done this before and am not sure how far in advance to bid. While I don't expect to change our plans, I realize reservations are non-refundable. I thought about waiting until 3-4 weeks before we go, but wondered if that might be waiting to long. Any advice is greatly appreciated.

Hi mlm,

If I were you I would go ahead and book now as long as you are certain about your dates. If you need more information on how to use priceline go to biddingfortravel.com

I have bid up to 6 months in advance. Go ahead and bid, if you are sure you are going. Just don`t overbid. You have plenty of time for rebids.

If there's any chance of a change of plans, I would book a backup cancellable reservation outside of Priceline now, and then use Priceline closer to the date when you are more sure.

Treck is right. You should really familiarize yourself with biddingfortravel.com. It will make you a smarter priceline bidder and will help you avoid making bidding mistakes like overbidding.
Make sure you read the hotel facts page on biddingfortravel.com...and take a look at what other people have bid in the California areas you will stay at.
To answer your question about bidding too early or too late, there doesn't seem to be any set rule about that. It all depends on what inventory the hotels have given to Priceline and each hotel may do things differently.
Good luck.