When he first joined the Manassas Police Department four years ago, Detective Edwin Rivera learned an invaluable lesson during his training: Always accessorize.

His field-training officer had taken him to the Virginia Arms Co. in Manassas to purchase extra equipment to supplement the standard gear issued by the police department.

Rivera's shopping list included items to make his life at work a little smoother: an extra pair of handcuffs, a metal clipboard to hold speeding tickets and a large nylon "kit bag" to store a flashlight, accident investigation forms, a rain jacket and other items that probably would get misplaced in his cruiser.

The bag, he said, was key.

"You need to know where those things are, because you'll need them in a split second," Rivera said. "You don't have time to think, 'Where are my [feet] restraints?' "

Many of Northern Virginia's police officers, sheriff's deputies and federal agents shop at area gun stores on a regular basis to obtain equipment that they say is so essential to their work that they don't mind paying for it.

In addition to purchasing on-the-job gear, many feel compelled to carry a weapon when they are off duty, in case they happen upon a crime or an old foe on the streets.

So they often purchase a second handgun, one that is smaller and more comfortable to wear concealed than, say, the .40-caliber Glock or 9mm Sig Sauer handgun they are issued. Buying an off-duty gun leads to further expenses: a second gun means a second holster, more boxes of ammunition and more bottles of cleaning fluids.

Sgt. Rich Perez, a spokesman for the Fairfax County Police Department, said officers are accommodated "as much as possible to ensure that they have all the appropriate gear as necessary," but getting all officers a smaller and more comfortable weapon for off-duty use is not practical. "We've got to make the most within the police department's budget," he said.

Phil Strader, a U.S. Capitol Police officer and firearms instructor who owns Shooters Paradise gun store in Woodbridge, said everyone's specific tastes cannot be met because police departments would take a "big hit" financially. Fair or not, he said, those who choose to become law enforcement officers enter into a field where people think differently about their work hours than most other government employees.

"A police officer's job is unique, because when does an officer have time off? Are you always on the job?" Strader asked. "A firefighter is not going to go to an emergency supplies store and buy a breaching tool. They're not expected to respond to things like that when they are off duty. Things are completely different for a police agency."

William Bunney, a detective in the Alexandria Police Department's vice and narcotics unit, said one of the main reasons he bought an off-duty weapon is that he wants to be prepared if he encounters someone he has arrested before.

"I run into people I put in prison at the oddest places," said Bunney, who likes buying his weapons and accessories at Potomac Arms Corp. in Old Town, where he worked after graduating from high school. "You run into them when you're shopping at a mall, when you go to the beach, when you go to dinner. I always want to have that edge if they decide to get even."

Jim Rowe, manager of Shooters Paradise, estimated that the store sold about 1,300 guns in 2003, not enough to cover the rent at the strip mall the store is in on Route 1. The real money, he said, is in the accessories.

Officers, Rowe said, buy different kinds of holsters -- shoulder holsters, high-ride belt holsters, front-pocket horsehide holsters -- badge cases and cowhide belts that can hold up heavy guns on their waists.

"My girlfriend works as diplomatic security officer for the State Department, and they issued her this big wallet for her badge that she can't fit in her pocket," Rowe said, eyeing a thinner badge case dangling from a store rack. "So I'm thinking about buying this one for her so she can carry it in her pocket."