Can you ever have too much security? Yes. Most definitely.
When the number of locks, keys and security doors are a hindrance to quick exit in the event of a fire or an emergency, then your security has become just the opposite: a danger.
I mention this as a result of several recent jobs in which my customers had bars on all the windows, double cylinder deadbolts and keyed knobs on steel barred security doors, and solid doors, equally protected, behind those security doors. This, to me, is over-security. Should there ever be a fire on the stove, an electrical fire, or any incident requiring an immediate exit, then the residents of these households are seriously at risk.
First of all, if cornered by a fire, the option of breaking or opening a (barred) window is off the table. Second, to make an exit, they can’t simply use an interior thumbturn to open the deadbolts. Oh no. Those double cylinder deadbolts require a key on the inside,as well as outside, and keys can be misplaced. Even if the plan is to leave a key in the lock, or hung near the door, that is not a safe, reliable system. Many people have different keys for their knobs and deadbolts, as well as for inner (regular) and outer (security) doors. They therefore have to come up with two separate keys to open two double cylinder deadbolts, one on the inner door, and one on the security door. If any of those keys are momentarily unavailable, then the resident is effectively locked in. Not a good proposition.
I have to fully respect the security concerns of those persons, many of whom are living alone, or who can’t readily defend themselves, and have to prevent any and all unauthorized entry. These are certainly legitimate concerns, and that level of security is certainly achievable without recourse to barred windows or double cylinder deadbolts.
I like security doors. They are an added level of protection, but need not be steel, nor barred.
Many security doors have upper and lower glass panes, with screens, and the security of a simple interior bolt which can be thrown easily and quickly, even by a young child.
As for the interior door, there is no substitute for a good quality, heavy duty deadbolt, a steel door, and a steel frame. These combinations will make entry through the two doors an onerous task for even a professional, especially if the locks are not pickable nor easily drillable. Medeco locks will do the trick. Even using a five foot crowbar on a steel door with a steel frame, and a Medeco deadbolt, is no walk in the park. Whatever system you decide upon, make sure that system allows instant egress in the event of an emergency. Keep in mind: double cylinder deadbolts are meant to prevent thieves from carrying large, valuable items out of the house. They are not designed to enhance difficulty of entry, nor to allow quick and easy exit!!!
Now, as for those barred windows. For about the same money as iron bars, homeowners can get high impact glass, which by the way looks so much better than bars.
I like alarms, especially really loud alarms, such as Klaxons.
They are very unnerving to persons you don’t want on your property, whether it be high noon or three in the morning. They make burglars scatter. They sound off immediately. No waiting for the police or a helpful neighbor. They are inexpensive, and need not be part of a security system. A simple push button klaxon might be a nice addition to your security setup. Kind of like a big, big dog, and just as scary.