Most burglars enter homes by simply opening unlocked doors or windows — or pushing and kicking locked ones until they open. So, before shelling out big bucks for an alarm system or other gadgets, first take some basic measures to improve your home’s security.

Many of the most effective security strategies cost nothing or very little.

Start with simple steps

Secure the perimeter: Make your doors and windows as difficult to penetrate as possible. Although intruders prefer unlocked doors and windows, many can quickly and almost silently pry open locked ones. Some break a pane of glass so they can reach in and unlock the window or door. Only a few really determined burglars break out enough glass to walk or crawl through, or bash in a well-secured door, and they seldom try to pick locks.

Get a security audit: Most police departments provide free advice and will send someone to evaluate your home for weaknesses.

Lose lousy locks: Key-in-the knob locks are inadequate. Install good deadbolt locks on all your exterior doors.

Secure sliding glass doors: The locks on sliding glass doors are notoriously flimsy. Many doors can be lifted right off their tracks. Numerous how-to videos on the Web can show you how to make yours more secure, or you can pay a locksmith to install reinforcements.

Replace weak doors: Solid-wood doors are much sturdier than hollow ones. Many homeowners in high-crime neighborhoods install metal bar doors.

Secure your windows: Depending on the type of window, you can take various steps to make it more resistant to a prying attack. Double-hung windows, for example, can be secured by screwing together the two frames. Most intruders are not keen on breaking glass, but it still happens often enough to justify concern. For the highest level of protection, the window should have unbreakable glazing or steel bars across it.

Keep valuables out of sight: Place articles of ostensible value out of the view of anyone at your front door or anyone looking through your front windows from the street. Stash cash and expensive jewelry in unlikely places — for example, in a large envelope or among many paper files. Select containers no one will accidentally discard.

Rent a safe deposit box: A box may be inconvenient, but it provides a level of security against theft and fire that cannot be duplicated at home for less than several thousand dollars.

Keep your landscaping in check: Doors and windows hidden by garages, bushes, fences, and trees are attractive targets for intruders who prefer to invade unseen.

Light it up: Many burglars will flee if they activate an outdoor light connected to a motion detector.

Keep track of your keys.

Get a dog: Many burglars avoid homes with noisy, furry, family members.

Lock up guns: Burglaries are major sources of guns for criminals.

In addition to improving your home’s physical security, adopt secure strategies.

Get insurance: Consider adding replacement-cost coverage to your homeowners insurance policy for your personal property. If burglars clean out your home, this optional coverage could save you thousands of dollars compared with standard coverage. If you possess expensive jewelry and other items covered at low limits under standard policies, consider taking out additional policies for them.

Get to know your neighbors: Neighborhood watch groups are one of the most effective ways to protect all the homes in your neighborhood. At the very least, get to know your neighbors and share information on your not-at-home schedules and vacation plans, so everyone can look out for suspicious activities.

Keep up appearances: Because most burglars strike when no one is home, make sure your house always appears occupied. Leaving lights and a TV on helps. If you go on vacation, work with neighbors or friends to prevent mail and packages from piling up and to keep your lawn mowed.

Alarming details

There is much evidence that home alarm systems do make a difference in deterring burglaries. They can also help prevent fire damage, and some alert you to power outages, water leaks, and other problems.

See Checkbook’s ratings of local home security companies and locksmiths free of charge until April 5 at Checkbook.org/inquirer/safe

In addition to conventional security systems, you can now buy easy-to-install gadgets that you can monitor yourself through smartphone apps and video feeds. Often, these devices can be combined with so-called smart home hubs like Amazon’s Alexa/Echo Dot to essentially create DIY security systems.

You can also buy dedicated home security systems from cable TV companies, Google, and Microsoft. Most offer an option to either use their devices to monitor your own home or pay more for professional monitoring. Facing rising competition from these alternatives, some home security companies now offer basic devices and systems you can install on your own and monitor yourself.

Don’t want a full-on alarm system or smart-home package? All these companies, plus others such as Nest, Wink, and Tend Insights, sell video cameras, sensors, and other devices that you can install in strategic locales and monitor for free using your smartphone — if it senses motion, it will send you an alert and you can watch the camera feed. Prices for these products tend to be cheaper than renting or buying from an alarm installation outfit; for instance, a Fortress Security Store glass breakage sensor is $35, Eva Logik thin window alarm sensors are $23 for four, and a Zmodo WiFi video doorbell is $60.

Checkbook recommends that homeowners first improve physical barriers to intrusion (some of which are discussed above) before bothering with any type of alarm system. Alarms can add protection against intrusions, but they also involve a significant expense and have some drawbacks.

Living with an alarm system is at best an inconvenience, at worst enough of a hassle that many homeowners don’t use theirs regularly. Although the more time an alarm system remains in operation the more protection it provides, homeowners continually turn off their systems to prevent false alarms.

Even if you purchase a home security system with all the bells and whistles, it might not do you any good if it’s designed poorly or installed sloppily. The ratings and reviews submitted to Checkbook, plus reports from its undercover shoppers, indicate that the expertise of home security representatives varies greatly. Checkbook’s shoppers met with several companies and found some knew little about actual alarm installation, spent minimal time inspecting homes, and seemed most interested in selling a predetermined package of equipment and monitoring services. On the other hand, some companies’ representatives were true experts. These salespersons had personally performed installation work in the past, and some installed the alarm systems they plan themselves. They took a good look around the house, checked inside closets, inspected the basement and other unfinished spaces, and banged on walls. They seemed to know exactly what we needed to protect the house.

You’ll also find huge company-to-company price differences. When Checkbook’s undercover shoppers collected proposals from companies for specific alarm systems and three years of monitoring services for four different homes, they were quoted prices ranging from $1,434 to $3,828 for one of the homes and $4,270 to $8,314 for another.

Delaware Valley Consumers’ Checkbook is a nonprofit organization with a mission to help consumers get the best service and lowest prices, and does not take no money from the service providers they evaluate.