Traditionally, the man pays for the ring and one popular guideline (admittedly perpetrated by the diamond industry) is that it should cost him a month's salary. It should be left to the individual to decide whether that's Net or Gross!

Should the engagement be called off by the bride-to-be, the engagement ring should be returned. If the man calls it off, she gets to keep it and, if she's got any sense, flog it to the highest bidder!

It's best to steer clear of second-hand rings, unless they are quality antiques or family heirlooms, and even then be careful. NEVER give a girl a ring you already gave to someone else and got back when it all went pear-shaped.

If you're giving her your great grandmother's engagement ring (potentially very romantic) make sure you offer to shell out to have it re-set and fitted for her, as she might appreciate the gesture but not the design. Check this won't break your mother's heart first.

Planning a surprise? Be sneaky and check your girlfriend's ring size by 'borrowing' one of her other rings, or tie a piece of string around her finger while she's asleep and marking it where it joins. Make sure you get the right finger (third finger of the left hand i.e. one in from the little one!).

Always keep the receipt. If she hates it, says no or if you ever need to make an insurance claim, you might need that receipt.

Insure your ring as soon as possible, just in case. If you plan to pop the question abroad, make sure it's covered by your travel insurance, in case it drops from your pocket on the way to that deserted desert island.

Some couples exchange rings on engagement, usually a signet ring for the prospective groom, in the same metal as his fiancee's ring.

Ring-buying tips

• Consider the type of wedding ring you want to wear, so the two will go together. Usually wedding rings are gold, white gold, red gold or platinum. The engagement ring generally looks better made from the same metal.
• Have your ring size measured properly (in any jewellers). The ring should not fit too tightly as in hot weather hands swell up and you won't be able to get it on or off (remember Sophie Reece-Jones?). Equally the ring should not be so loose that it slides round on your finger, or over your knuckle too easily.
• Diamonds are traditionally the most popular stone for engagement rings. This is because the diamond's scarcity and durability is supposed to symbolise the constancy of the love declared by the couple! Sapphires come a close second (though this didn't work for Charles and Di), followed by rubies and emeralds. Many engagement rings are designed with a main (larger) stone, set with diamonds around it.
• There are thousands of styles of engagement ring to choose from and bearing in mind that it will be worn for a lifetime, it's worth taking your time and choosing the right one. Don't be pressurised into a purchase (you can browse at your leisure on confetti.co.uk) so shop around and make sure you buy from a reputable company.