In determining the reasonable value of attorney’s fees for services rendered, the proper factors to be considered are the amount and character of the services rendered, the labor, the time, and trouble involved, the character and importance of the litigation, the amount of money or value of the property affected, the professional skill and experience called for, and the standing of the attorney in his profession; to which may be added the general ability of the client to pay and the pecuniary benefit derived from the services.