It will be always advisable to have a reliable locksmith service in your phone book even if you are not need of it. As it cannot be expected when will the need arises and if you come across a situation where you get your car or house locked then you will realize the need for it. This is because that good locksmith is not as easy to get as they should be more professional and reliable.
In case of emergency you may find a locksmith by going through your local phone directory and you may be surprised you may have the number in your local phone book but their offices may be miles away from you. When you call them for assistance they may send a locksmith who may or may not be well trained. By getting an untrained and wrong locksmith service provider could destroy your lock and door which will end up in overall bad experience. That's the reason why you should go for a good locksmith service provider even if you don't expect to get locked out anytime soon.
You should look out for a service provider with a local office. It is important that they should operate 24 hrs a day, seven days a week. Find out whether they are having the right licences and permits and the service provider should be able to update their staff about any advancement in the lock technology.
You can take the advice of your friends and family have experienced the service of any of the locksmith service provider so that you can get hold of trust worthy locksmiths. In any point of time they had been lucky enough to get the services of the locksmith who had the skills and the knowledge to help them in their time of need. You can also approach your car or home insurance agent for some suggestions. If these people recommend someone to you try to get their calling card or contact number such that it will relive you from the burden of searching for such information on the phone book or on the internet.