Are there trustworthy contractors out there, hell no! Yes of course there are some great ones and then again, perhaps not always!
Working with a licensed contractor to obtain cost and time estimates, including special inspections and permits, all in a timely manner is of course best.
https://www.cslb.ca.gov/consumers/
A few diligent ways to check is to:
Ask for project references of similar jobs.
Double-check in project type and verify the ability to complete projects on the schedule made and on budget.
Request a site visit, written proposal and an anticipated schedule
Think about the fact that every contractor has a different dynamic under which they must work or operate their businesses. Each one should be completely understood, and all terms and conditions be accepted before they begin to tear your building apart. Take extra care to have all points clearly itemized in writing and only work with a reputable company.
While most people look for the lowest price in the hopes that everything they need will be seamlessly taken care of without further expenses or effort, it is almost never that straightforward, certainly never easy and even if expected, additional expenses are rarely welcomed.
Now let’s put ourselves in a typical contractor’s shoes. Foremost, he/she must be competitively priced, enough to be considered at all. Whether his price is slightly more or slightly less than you expected, he must make a reasonable and fair profit while satisfying his obligations to you, his crew and his bottom line.
Not all contractors are operating inefficiently, not by any means, but there are those that might take on as many jobs as they can get, sometimes losing money and control. It can be frustrating should your expectations not be met, especially after you have spent your money and committed to a contract.