How long between marathons?

The convention is two a year, one in the spring one in the autumn. This should give you time to recover properly, train well and taper. I have done 3 so far this year with my 4th in two weeks, another the month after and a 30 miler in December. But I only raced / will race two of them the rest is just for fun.

So people do them every month/week but they are clearly insane and best avoided

It really does depend on your fitness. Some people do 3 marathons in 3 days (Beachy Head, Snowdonia and Dublin) but you have to be incredibly fit to even consider that.It's impossible to advise you without knowing more about you, and your goals. 

Hal Higdon has a good article on multiple marathons here: http://www.halhigdon.com/marathon/multiple/Multiplemara.htm 

The fundamental requirement seems to be that you maintain a good level of mileage throughout the year.

Back to the original question.

It all depends on your fitness, endurance, how long youve been running for, how much you're used to training etc.

A regular runner /even relative beginner should be able to compete at 2-3 marathons a year, i.e. be fully recovered, re-peaked their fitness and taper. 

There's nothing stopping most people running a lot more marathons a year, more frequency will just mean you're not at your peak fitness so will suffer more from underlying fatigue.  Most people will therefore tend to pic a couple of 'A Races' which are their target races for the running season.

If you want to be at your best I would suggest leaving a minimum of 3 months between races.

Devoted2Distance wrote (see)

How are they not injured?

Distance doesnt equate to injury, though it takes a long time, gradual build up and frequency of running to be able to run 100 miles in a day.

Cos we train for em!

Becca...it does depend on your recovery really. I've done back to back 40 milers before...40 mile race sat, then 40mile race on sun and then ran with the club on the monday, but my recovery is good. Between my first mara and my second, I had four months....then six weeks to the third....four weeks to the fourth.....bit addictive these maras

I was reading an old RW the other day - an article about Ultras, and it said most people don't actually train for these 100/100+ mile races...so how does that work then?

Hope to run one myself one day.. think I need to sort my biomechanics first though - otherwise, I'm going to be in big trouble. Only 23 after all. Don't want to end up not being able to walk when I'm 30..

I'd strongly advise entering 2 marathons a good 5/6 months apart, and give it yer all in both. Even if you're working off a good base, you need to devote 3 months to marathon training (and warm-up races), then it's a good month after the race before you even want to think about running another race. Then if you know you've got that time to recover before hand, you can devote more effort to the marathon training. 

People who run multi-marathons, or on consecutive days, etc. are looking for a different challenge, more like the ultra-marathon mind-set where it's more about the mental aspect of endurance than pure athletic ability.

You say you can imagine running marathons way into the future.  Another advantage of doing Spring/Autumn marathons is that you get to train in different seasons to see which you prefer.  So you might find it harder to do long runs when it's warm, or do you prefer the longer evenings?  5/6 months from May (after Edinburgh) is Oct/Nov. There are loads of maras around that time, certainly major overseas ones but there would be more local races as well.

Thanks for your replies everyone

PhilPub wrote (see)

5/6 months from May (after Edinburgh) is Oct/Nov. There are loads of maras around that time, certainly major overseas ones but there would be more local races as well.

I've just discovered that there's going to be a marathon in Bradford next October, so I reckon I'll give that one a go as well as Edinburgh. Should definitely be enough time to recover and train, plus it's nearby

have you not read about eddie izzard d2d........should answer your question (training effect etc)

Re the OP - i ran london this yr and have dublin in 5 wks, i've entered edinburgh for may - so excited - and hope to do an another overseas one in the autumn, seems to be doable, gave me a rest and my fitness has definatley improved as well as my speed.

If you have the bug, go with it and enjoy - i am !!