So, what was considered safe and effective years ago may not be considered that now. Does it really mean that everyone must drop what they're doing and change their water heater so its 18" off the floor or add arc interrupters in their bedroom electric? Safer is better, but there is a point where we all just grandfather those old ways, rather than change our electric and plumbing every few years to keep up.
Usually code changes indicate that some problems were found and the powers that be decided to force everyone who builds new or touches that item to bring it up to code. No, they don't normally force you to comply, unless you are building or re-modeling and touch that item.
Should you? This is your call. If it made sense years ago the way it was built, but not now that's one thing, but if it was built wrong to that old code, you should definitely have it remedied. Talk to a professional about the consequences of not changing if you have a choice and then decide.
Lynn911 Dallas Realtor & Consultant, Loan Officer, Credit Repair Advisor
The Michael Group - Dallas Business Journal Top Ranked Realtors