Bendigo Police are appealing to tradesmen and business owners to take extra care with their tools and computers following a spate of thefts from unlocked cars.
Senior Constable Jamie Stubbins said thefts were happening on a daily basis.
"Don't leave spare keys in the shed with your car. Don't advertise that you're leaving your house for long periods of time," he said.
Senior Constable Stubbins said tradesmen should record the serial numbers of their tools in a notebook so that valuables are easier to trace if stolen.
"They're worth thousands of dollars and people don't bother to record the serial number," he said.
He said serial numbers of computers and tools should also be engraved, in case thieves remove labels.
He said Bendigo Police were noticing criminals were less likely to smash windows and more inclined to open unlocked doors and look for valuable items.
"They're just after a quick, open the door, have a look."