If he’s already popped the question, or you’re just hoping he’ll ‘do the honourable thing’, or you’re considering making an ‘honest man’ of him yourself (after all this is a leap year), whatever the scenario there’s one important thing you need to consider. The Ring.

The diamond engagement ring as we know it has been around since the 1400s. And whether you’re proposed to or not ladies, I think it’s important to stick with tradition here. So, before you go any further, girls – and boys - here are the 10 rules of Engagement …. Rings.

Guys, I’m talking to you here.

1. Trick or treat?
First thing is to decide whether your girlfriend will really appreciate having a surprise ring foisted upon her. Popping a ring onto her finger may be the traditional way to propose, but most girls will have been daydreaming about the style of engagement ring they want for ages. And most women would prefer having some say in what sort of ring they get.

Buy her a rock that’s too small and she’ll think you’re tight; splash out on a 3 carat monstrosity and she’ll think you’re vulgar. Don’t take the risk. Just let her choose, OK? On the plus side, what woman is going to turn down a proposal that’s accompanied by the words ‘and you can choose any ring you want’?

2. Size does matter
However, if you are planning a surprise then nab one of your future intended’s rings, preferably one she wears on her ‘ring finger’ so you can get a good fit. Don’t worry too much though because most jewellers will be happy to alter it if the ring you choose does turn out to be too small or too big.

If you’re getting a ring made to your own design many jewellers will suggest handing over a plain band and then letting you and your fiancée finalise the design together. That way everyone will be happy. You’ve done the romance bit and she gets to be involved in the creative process too.

3. Just like granny’s
If you’re an old-fashioned sort of guy and want to hand over your grandmother's engagement ring you will probably want to get the stone re-set in a more modern setting and the band adjusted to fit. But get the OK from other family members first who might have other ideas.

4. Diamonds are a girl’s best friend
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 your love for one another. Aaah sweet. Sapphires come a close second (though this didn't work for Charles and Diana), followed by rubies and emeralds. But ultimately the choice is yours (and your wallet’s).

5. Remember the four Cs
These stand for cut, carat, colour and clarity. When you delve into the world of diamonds you can feel like you need a PhD to make sense of it all. It can be mind-boggling – and doubly so when you’re shelling out a small fortune on a tiny bit of rock. But do your homework before you hit the shops and you shouldn’t go far wrong.

Most of all relax. This is supposed to be enjoyable. If you both like the ring, the price is right and you’re buying from a reputable retailer there’s really no need to have nightmares over cubic zirconia fakes.

6. Don’t forget the fifth C
Cost. Some wedding folklore suggests one month’s salary is what you should pay on an engagement ring for your intended. Others say two months is more like it, while Americans insist on three. Whether they mean before or after tax is for you to decide. I would suggest you have your top-whack price in mind and then try your best to keep within it.

It really comes down to what you both like and feel you want to spend. Just don’t get carried away. Although ultimately it’s for you to decide whether it’s worth getting up to your eyeballs in debt just so she can have a ring ten times the size of her best friend’s/her sister’s/her mother’s/her boss’s.

7. Something old, something new
If you buy an antique engagement ring, you'll be buying something original that you can't find in a high street jeweller. Scan the styles and get a feel for what you like. Then, depending on your budget, you can try the smarter jewellers, antiques markets or buy at auction. If you buy at auction, browse through the catalogues, and then visit the experts on viewing day.

If you do opt for an antique ring and fancy something other than a diamond the experts advise you to steer clear of three stones. They are turquoise, because it can discolour; opal, which is also prone to discolouration and can crack; and pearls, as they're very porous and, once damaged, lose their lustre. Victorian rings are best at standing up to everyday wear and tear.

8. Sloppy seconds are a definite No-No
Under no circumstances should you consider popping a ring on her finger that you’ve already given to someone else. It might be the biggest diamond solitaire this side of the Crown Jewels, but just imagine the reaction when your fiancée finds out it wasn’t bought specially for her. And she will find out, women always do.

9. It takes two to tango – and two to get wed
When you’re choosing the engagement ring consider the type of wedding ring you want to wear, as the two will ultimately be worn together. Choosing a matching metal is usual, although not essential. If you’re picking an unusually shaped ring make sure you can get a wedding ring to fit next to it. If you have to get one specially made, consider the additional cost.

10. Accidents can happen
Insure your ring as soon as possible, just in case. Most home contents policies will accommodate you – call your insurer (or get your fiancée to call hers) to discuss the details.

And if you plan to pop the question abroad, make sure your ring’s covered by your travel insurance – just in case it drops from your pocket on the way to that desert island. And always keep the receipt. If she hates the ring, turns you down or you ever need to make an insurance claim, you’re going to need it.

Done that, now what?
Great. Now that’s sorted all you’ve got to worry about is the Big Day itself. So have you decided who you’ll you be inviting and not inviting? Whether you want a big or small affair? Got your dress? Set a budget? Thought of the flowers? The cake? The car? The honeymoon?

And you thought proposing was the scariest part?