Washington Redskins tight end Chris Cooley used to go to work with his house unlocked, his garage door open and his mind at ease.

Living in a distant suburb of Washington, D.C., Cooley never worried about break-ins or robberies. He had even less concern about getting beaten, shot, stabbed or killed.

That was before the death of teammate Sean Taylor, who died a year ago Thursday, a day after being shot at his South Florida home during a robbery. Cooley has made substantial changes to his security habits since, and he's hardly alone. Taylor's death and the late-night attack on Jacksonville Jaguars offensive lineman Richard Collier this year have forced the Redskins, Jaguars and many of their colleagues to adjust their lifestyles — minor deviations for some, radical transformations for others.

"Probably both of them could have been prevented by simple security measures," Cooley said. "That's sad to say, but it's the truth."

Guard dogs, alarms, cameras, motion sensors and firearms, some of these guys have it all. They double-check windows and doors daily, keep close tabs on who's coming to their homes and try to avoid dangerous situations — even if it means a boring evening at home instead of a night on the town.

"Those shootings have thrown my antennas way up and shown me that even when you think you're safe you're not safe," said Jaguars safety Pierson Prioleau, a teammate of Taylor's last season.

Although Prioleau upgraded his home security ("If ADT has it to offer, I got it," he says) his most important change has been in awareness.

"I am more cautious, more aware of my surroundings," he said. "I am more careful of the people I invite in my home, the people I surround myself with when I go out. I had a security system before and I had guns before. Now, I'm just more alert."

Prioleau checks around his car before he unlocks the doors, keeps an eye on his rearview mirror to make sure no one is following him and tries to never stop in a poorly lit area.

Teammate Dennis Northcutt takes similar precautions, but he believes that if someone decides to attack him and plans it right, there's nothing he can do to prevent it.

"Some things you just can't prepare for," Northcutt said. "You can get security. You can have the biggest gun, the biggest knife, the best whatever you want, but sometimes that just doesn't even matter. If you get caught in the right moment, the right situation and they plan right for you, then it's your time. It's unfortunate and it's hard, but it's the truth."

Taylor, a Pro Bowl safety, was sleeping at his home in an affluent Miami suburb, along with his longtime girlfriend and the couple's 18-month-old daughter, when they were awakened by loud noises. Taylor grabbed a machete he kept nearby for protection, but it did him no good when the intruder broke down the bedroom door and fired two shots, one striking Taylor in the leg and ripping through a vital artery. Taylor died a little over 24 hours later. He had failed to turn his security system on even though his home was burglarized a week earlier.

Collier was shot in early September while waiting for two women outside an apartment complex. He sustained 14 gunshot wounds and had to have his left leg amputated because of blood clots. Police said the man charged with shooting Collier wanted revenge after they fought outside a nightclub in April.

There are plenty of other examples of violence against athletes, too:

—Broncos cornerback Darrent Williams was shot and killed outside a Denver nightclub while riding in his limousine in 2007.

—Oakland receiver Javon Walker was robbed and beaten unconscious in Las Vegas in June.

—Houston cornerback Dunta Robinson was tied up in September 2007 while two men broke into his home and stole jewelry.

—NBA players Antoine Walker and Eddy Curry were robbed just weeks apart apart in their Chicago-area homes in 2007.

While the NFL provides security consultants and teams have their own security chiefs, it's really up to the players to change.

And most have.

Jaguars running back Fred Taylor considered getting a guard dog, but since his wife doesn't like dogs, he purchased an AR-15 military rifle instead.

Redskins running back Rock Cartwright and linebacker Khary Campbell also bought guns.

"I keep it in my house at all times," Cartwright said. "I keep it loaded. I keep it in a secret spot — only I know where it is — in case something was to go down. You've got to protect yourself at all costs."

Teammate Chris Samuels took a different route, getting two trained security dogs, lights all around his home and motion sensors for spots near the wooded areas.

"We're targets whether we like it or not," he said. "I am taking extra steps. I've got people watching the house and stuff like that when I'm gone."

There are some who haven't changed a thing since the shootings, calling them isolated incidents and random acts of violence, and pointing to the odds being in their favor that this kind of tragedy won't happen to them.

But many, especially the Redskins and Jaguars, aren't willing to take that chance. That's why Cooley now locks his place down when he leaves for work.

"I was nervous for six months after Sean died, about people being in your house," Cooley said. "Basically, if somebody really wants to be in your house, they probably can. So, we were smart. We took security very seriously. We went and got a couple of cameras and we were serious about an alarm system. We keep our house locked up. People do know your schedule, they know what you're doing, and so you've got to be safe about that."