Employers must keep accurate information of time records showing:

• When the employee begins and ends each work period
• Meal periods
• Split shift intervals
• Total daily hours worked
• Dated properly – showing month, day and year

Employers do not have to record meal periods where all operations cease.  Employers also do not have to record rest periods

Time records must be maintained

• In English
• In ink or other indelible form (i.e., cannot be erased or removed)
• At the place of employment or a central location

You should also ensure the data being saved are the actual time records of employees and can be reproduced in a format that is accurate and easy to read.

Although the Labor Code Statute of limitations for wage claims is three years, the statute of limitations on unlawful competition claims related to wage and hour claims can extend back four years, so employers should keep time records of all employees for at least four years

This means the time during which an employee is subject to the control of an employer, and includes all the time the employee is suffered or permitted to work, whether or not required to do so.  An employee who is subject to an employer’s control does not have to be working during that time to be compensated under California law. 
Problems for employers arise in situations where employees engage in certain pre- and post-shift activities like donning and doffing uniforms, loading and unloading equipment and tools for the day, setting up and shutting down a work area, and security checks.  Issues also arise when employees show up a few minutes early to clock in and drink coffee until their scheduled starting time in order to comply with an attendance policy.

Sloppy, inaccurate, or inadequate time records will be used against you to form the basis of costly wage and hour class action lawsuits.
California law is clear on this issue.  Once an employee submits evidence that he or she was not paid for all hours worked (i.e. through an employee’s own testimony or evidence of a company policy or practice), the presumption is the employer did not pay for all the hours worked until it meets the burden of proving otherwise.  The fact that the precise amount of time is difficult for an employee to prove because of the employer’s inadequate recordkeeping will not be counted against the employee.
Similarly, if meal period records show missed lunches, lunches less than 30 minutes, or lunches that did not begin until after working 5 hours in a shift, the courts presume the employer did not provide them in compliance with California law unless the employer can somehow prove otherwise.

For meal periods? No!  The California Supreme Court has ruled that rounding meal period times is not allowed.  You must record when employees actually begin and end their meal periods.
Rounding time entries for the beginning and ending of shifts is permitted if it “is fair and neutral on its face and ‘it is used in such a manner that it will not result, over a period of time, in failure to compensate the employees properly for all the time they have actually worked.’”  See’s Candy Shops, Inc. v. Superior Court (2012) 210 Cal.App.4th 889, 907.
Rounding time entries for shift time is very risky because it is easy to screw up.  The problem is usually how the rounding policy works in practice such that it underpays employees over a period of time.  In fact, just by having a rounding policy exposes you to a costly wage and hour class action lawsuit regardless of whether it is legally compliant.