Police are warning householders in Sunderland and South Tyneside to lock out thieves this summer.
Northumbria Police said around a third of house burglaries in both areas have taken place after a door was left unlocked or a window open since February this year.
And, with the onset of warmer weather when people tend to spend more time outdoors in the garden and leave doors and windows open, police want to make sure unwanted sneaky burglars don't have an open invitation into homes.
Almost 40 people have been arrested across Southern Area Command for house burglaries since May 1. Nine of those people have been charged with the offence.
Earlier this month a burglar was jailed for three years after he snuck into a house through an unlocked door and stole a tablet and personal papers from the occupants. The burglary happened in the early evening in South Shields last December.
In a separate burglary one resident in Sunderland's Downhill came face to face with a burglar in the house - the burglar had climbed through an open window. He has been charged and remanded in custody, awaiting court.
Southern Area Command Chief Inspector Jerry Pearson, said: "My concern is that as the weather starts to warm up people will be spending more time in the garden and will leave the front of the house insecure. If they're in the back garden and the front door has been left unlocked or a front room window left wide open burglars can be in and out of the house without the occupants even knowing - even though they are only in the back garden.
"It is really important that people consider burglary prevention measures and not think that it will never happen to them - unfortunately the truth is there are burglars who actively go around looking for easy pickings and opportunities where they can steal with minimal effort and an insecure home is an open invitation to them.
"My advice is always lock the front door even if you are in the house and if you are not in the room make sure the window is closed, even if it is a back room and does not look onto the street, if you leave the room close the window. This is particularly important overnight or if you go out. Never leave valuables near to the window, or items such as car keys, wallets or mobile phones near to the front door.
"People can take more sophisticated steps to help prevent them from being burgled, such as burglar alarms and security lighting, but ultimately if the front door has been left unlocked these are going to be pretty ineffective in preventing a burglary."
Police are also extending burglary prevention advice to outbuildings, such as sheds and garages.
Chief Insp Pearson added: "People often forget the value of items in their sheds and garages but if you're keeping items such as gardening equipment, bikes and tools inside it all adds up and becomes an attractive target for burglars. Again, I would urge people to make sure they keep outbuildings locked and make sure the lock is good quality that isn't easy for a burglar to break. Don't leave expensive items out in the garden lock them away until you need them."
The advice comes as Operation Impact continues to target burglars across Sunderland and South Tyneside.