Heathrow is the only airport I can recall passing through where there are free public scales located outside the departure area. I always use them to check the weight of our luggage. Elsewhere you appear to be in the hands of the airline check-in staff who are anxiously waiting to separate passengers from their money.
Whilst we have a very generous luggage allowance from Hong Kong to Heathrow the same cannot be said for our flight from Sydney to Hong Kong. Departing overseas for five years with your worldly possessions in one hand is not impossible, but you naturally want to ensure you have used all your allowance.
Using 8200 of my Frequent Flyer points I have purchased digital hand held scales
The accompanying information states
Balanzza Ergo Digital Luggage Scales - BZ200
Avoid excess luggage charges with Balanzza Ergo Digital Luggage Scales. Weigh up to 44kg in increments of 50g. Easy 4 step operation. Attach, lift bag, wait for beep and put down to read displayed weight. Dimensions: 16cm (L)x 4-6.5cm(W) x 2.5cm (D). Product weight 215 grams.
With some careful planning we will be able to juggle the content of our suitcases to ensure we achieve our maximum allowed weight allocation.