This question is regarding check-in, not carry-on, baggage.

I saw a very spacious suitcase measuring 31 x 21 x 15 inches, for a total of 67 inches. This is greater than the 62-inch limit most airlines have, except for Emirates, which decreased its limit to 59 inches.

Is it safe to buy this oversized suitcase, or should I stick to the letter of the rule, and therefore with my existing suitcase, which does comply? 

The reason I ask is that I've had my check-in suitcase weighed several times, but never had its dimensions measured, as far as I can remember. Have you faced any trouble because of this? Or is it safe to buy this suitcase?