If, as we are led to believe, the doc is currently in his 10th incarnation, how can he possibly be 900 years old? Did each of his previous incarnations average a life span of 100 years? In most cases we know this not to be true due to the continuity within the series. How do we account for the 'missing years'?

I fear I am becoming more of a geek each day

Hiya

The Doctor ages about a 100 years everytime he regenerates but because he's not human he continue's to live. Hope this helps with your question

The first Doctor did seem to already be quite old when we first met him, maybe he'd lived a long, relatively quiet life before the show started. We also don't know how long he spent in his 7th and 8th bodies.

We also haven't seen all of the Doctor's adventures onscreen (hence why the Big Finish CDs and the Who books are able to fit in to the lives of different Doctors)

the first doctor was already old, and I think he's cycled through his regenerations pretty quickly since then (he really should be more careful!)

Yeah He was roughly 450 years old when he first regenerated! During his 4th life he mentions being around 753 years old and during his 7th he said he was roughly in his 950's. Taking into account his later years us at Outpost Gallifrey have estimated that he is more accurately somewhere around 1150 years old. Of course Timelords themselves usually respectfully only carry around 900 year diaries so any age after that you probably just stop counting hence the 9th Doctor saying "I'm getting old!".

Just thought I'd give my 2 pence worth!!!

see you soon

there are many more Doctor Who adventures,,, we dont see them all on TV!
Books CD's Podcasts!!! the list goes on, we even have companions that never appear in the TV series,, a shape shifter that got stuck as a Penguin, (Frobisher) comes to mind!

What we do know, is that the Doctor is currently in his 10th regeneration, and a timelord only has 12 Regenerations,,,,,,so as long as he looks after himself, he can live a very long and stressful life! But then again 12 can become 24!!!! A complete new life cycle!

I wonder if the new series will go as far as the 13th Doctor and kill him off for good? Or will they do the same thing as they did with Doctor no.7 and leave the door open?

It has been suggested that he is counting his years from the time when he first landed in 76 Totters Lane before the events of An Unearthly Child, and lying about his age through vanity! He mentions 900 years of 'phone box travel' in The Empty Child meaning that if he arrived in London at 440 years (the First Doctor travelled with humans from Earth throughout his on-screen adventure), he is really 1,340-ish years old.

I think his age is unrelated to the number of regenerations he's had. In the relative safety of Gallifrey he was able to clock up almost 500 years in his first body. After that, he was pretty much dodging a bullet every day of his life so it's not surprising each incarnation didn't last as long as the first.

I think you can judge/guess how long each incarnation has lasted – in terms of the Doctor’s age - by looking at his companions. Peter Davison’s fifth Doctor, for instance, didn’t have a break between companions.

I had the impression his first season (with Tegan, Adric and Nyssa) took place over a period that was less than a year. There was a gap between his first and second season, but Nyssa didn’t seem to have aged and so if there was a break it would have been fairly short (there was certainly no suggestion he had dropped Nyssa off and then go on off on his own for a few hundred years).

His second season (with Tegan, Nyssa and Turlough) seemed – again – to be pretty tight between each story. And in his third and final series (with Tegan, Turlough and Peri) the stories pretty much rolled straight from one into the next. So, in all, my guess would be that the fifth Doctor only lived for about three years – pretty much as he was on screen.

The same could be said for Jon Pertwee, especially as such a great part of his time as the Doctor was spent in a continuous Earth environment. Again, there was no suggestion he had popped off for a few hundred years between stories.

Other Doctors – Colin Baker onwards – are far more difficult to judge because there is much more room to believe they had plenty of off-screen adventures. For instance, we don’t know for sure that Melanie joined the Doctor soon after Peri left. There could have been a gap of hundreds of years for all we know.

That said, his age should still be going up rather than down so it is odd that he says he’s 900 years old when Sylvester McCoy’s Doctor put his age at about 950.

Does CE say he's 900 years old, or just that he's had "900 years of phone box travel"?

In actual fact, he's probably just over the 1000 by now!

He was over the 900 year mark when he landed in London in 1963 so obviously since in our time, 43 years have passed, he's obviously in his late 9002 or early 1000s.

Although he reckoned he was only 450 after his second regeneration, he was alking in relative terms saying that his body was now at the stage it would have een when he was 450. He can't actually lose years from his existence.

Doctor 9 claims he's 900 but when you're as old as that, you probably lose track of a few years here and there.

Plus he's been known to knock a few years off now and then (if I recall correctly) as did Romana.

Absent-mindedness, or vanity?

Who knows? Anyway, he'll soon be middle-aged!

Lol quite true - but with Romana being such a whippersnapper I'd say it was probably vanity on her part.

There is a theory (that has done the rounds for years) that when each Doctor gives his age, he is speaking for that incarnation only. I don't think this damages continuity, to be honest, but I can't remember seeing anything from the series to prove or disprove it.

He has a time machine, he could spend 800 years doing something else and then come back to earth 5 mins after he left us.