I've been in LE 23 years and counting, and I have taken plenty of burglary reports, read hundreds more, talked to tons of thieves (including a few I made on prints with no other leads) and even been a victim of home burglary once or twice myself. I certainly don't know it all, but I do know an awful lot about this type of stuff from plain old experience.
I have learned a few things over the years....one is no two thieves are the same so there is never a one size fits all solution, but most are strict opportunists and follow a similar pattern (especially the younger ones who haven't had time to sit and listen to the pros in prison).
Most daylight crooks will cruise about the neighborhoods looking for easy marks, either in a car or on foot (teen aged hoods walking home from school are good at this). Papers in the driveway, cars all gone to work or vacation, no dog, no alarm sign, etc. They will try the doorbell or knock looking for a response, and they will gauge the interest of the neighbors who see them. (More thefts are prevented by people who stop and take a look at folks who don't look right than anything else.)
Daytime types will usually kick the door or break the slider or window to get in, check the usual spots* for cash, handguns, jewelry in that order, then vamoose in under 5 mins. These things are easy to conceal on the getaway, and easy to sell quickly....and cash never has anyone who questions it. Those who work in pairs with a vehicle, or who live very close to the victim, will add electronics like TV or stereos to this shopping list so they can toss them in the car or run to their place quickly. I have even seen where some crooks rent U hauls and empty entire houses pretending they are hired movers. Rare, but it happens!
Nightimers will also cruise a neighborhood, but they prefer to be anonymous, so they will not often knock on doors. They will usually gain entry through unlocked doors or windows, or pry a window or slider to get in quietly. They will look to Grab the purse or wallet on the kitchen counter, maybe creep into the bedroom and take what is in the open, then vamoose.
Thieves are not dumb, they want to look as inconspicuous as possible and most don't want to meddle with a safe because they are running against the clock. When I got burged I was out of town. I lost TV, VCR, cameras, watches, and a new pair of Sorel boots. The gun locker was untouched even though I have a garage full of tools. No one in my crappy old neighborhood said they saw a damn thing.....but I think the tweaker dudes from 4 doors down the block did it.
Now, if you ADVERTISE your guns with a H&K sticker in the window of the truck or a Protected by Smith and Wesson tin sign on the porch, you may attract those crooks who specifically look to take a safe or locker and the contents inside. (Either that or a home invasion robbery crew, which are far more likely to cause a gun battle) You better believe that any determined gun thief will bring what it takes to open or remove a safe or locker and get the guns inside, so your best bets are to not advertise your valuables and to make your place as thief-unfriendly as possible. And yes, while nothing is ever going to be 100 percent thief proof, a decent safe will make the difference between losing your stuff and keeping it the vast majority of the time.
Stay safe!
* master bedroom night stands, dressers, closets, under beds, etc. There are almost always tossed in every burglary i can recall because this is where most folks keep jewelry, cash and unsecured guns. Kids rooms, other closets, bedrooms, couches, garages are down the list for many crooks.