Items like jewellery, share certificates and mortgage documents are sometime stored in unsecured places in the home, according to self-storage company Need More Space.
"This trend, known within the industry as the 'biscuit bin trap' is said to be responsible for people losing these items as a result of either misplacing them or, now worringly, through theft," it said.
While thieves often target obvious items like valuable jewellery, laptops, camcorders and MP3 players are also high on their list.
"It's a terrible inconvenience when any item is lost or stolen, but the real loss arises where there are no back-up copies of certain articles," said Colm Hefferon, managing director of Need More Space.
"A laptop or MP3 player can always be replaced, but it's the unique and personal information stored on them that are simply irreplaceable and could potentially be lost forever.
"Many people may not consider their 'digital valuables' to the same extent as tangible items such as wedding rings but if you lose the one and only copy of your wedding video you'll quickly come to realise its sentimental value," Mr Hefferon added. Many people may not be aware they have multiple options with regard to safeguarding valuables, but the emergence of self-storage offered "a safe and viable alternative", he said.
Self-storage units are protected by 24-hour security and people have the option of accessing them whenever they desire, Mr Hefferon said.
Customers storing their valuables can gain access through a unique PIN that grants exclusive access to the secure individual storage units.
Need More Space has three facilities around Co Dublin: at Deansgrange, Santry and Kylemore.
It currently provides storage and logistic solutions to more than 1,000 home and business customers, it said.