This could have been worded 'Care of your pH meter during school holidays', as these are the main products that require attentions. However, for all battery powered products, it is worth taking the batteries out before putting the meter away for the summer holidays.
For pH meters it is the electrode that needs to be kept maintained in order to pro-long the working life of the system. If you have a pocket tester then it is just the electrode end that needs keeping wet - not the whole instrument!
After the holiday period, the pH meter may appear slow or sluggish to respond, in which case put the electrode in pH 4 buffer solution and leave overnight. Then try calibrating it the next day, this can often 'wake' the electrode back up after it's summer holiday.
