does the date really matter

Im still undecided about which lens to get to replace my 150-500 sigma. The date of production does it really matter for the 100-400l?

Older glass just means it was made a while longer back. Generally, as equipment gets older the chance that the equipment will malfunction increases. It's just another value used for consideration. You can't really judge a lens's condition just from the age since it depends a lot on how the user used it. I personally like buying more recent equipment.

Well, Im wondering is there a good year for certain models.

Its the package you get that maters.

I bought a used 135L from B&H Photo this year that the date code placed it as being manufactured in 2006. The lens that I took out of the box and pouch could not have been in more pristine condition if it were new. Glass and body looked untouched straight from the factory fresh.

I've seen 10-15 year old lens that when properly cared for I wouldn't hesitate to purchase. On the flip side, I've seen almost new lens sold on here and elsewhere I wouldn't touch by the way the previous owner treated them.

torkk wrote in post #15378374
Im still undecided about which lens to get to replace my 150-500 sigma. The date of production does it really matter for the 100-400l?

Get a Canon 400F5.6 - new or used depending on your budget. It has significantly better IQ and AF than your Sigma and, with a little cropping, will give more reach due to the better IQ.
If you are buying used then look at the condition rather than the date. If a lens looks mintish then, generally, it will be good for some years to come.
I no longer buy new lenses as they are too expensive and most of my lenses are second hand and I have had no issues.

I thought of the 400 f5.6 but the lack of IS bothers me

torkk wrote in post #15379288
I thought of the 400 f5.6 but the lack of IS bothers me

I'll take the lack of IS over inferior image quality any day. The IS on the 100-400 isn't all that great anyway. Just keep your shutter speed up around 1/1000 or more and you will be fine. Which is easier to do on the 400 5.6 since it's sharp wide open unlike the 100-400 that has to be stopped down to around 7.1 or 8

SVTmaniac wrote in post #15379313
I'll take the lack of IS over inferior image quality any day.

Is that what you meant?

Nightdiver13 wrote in post #15379386
Is that what you meant?

Yeah that's what I meant. I'm all doped up on cold medicine right now. Thanks for helping me out.

I bought glass that was 14 years old. Works like a charm. Condition was around an 8/10. Price was decent. All depends how comfortable you are buying used.

torkk wrote in post #15378374
Im still undecided about which lens to get to replace my 150-500 sigma. The date of production does it really matter for the 100-400l?

I had the Sigma 120-400 and the Canon 100-400. The Sigma had better IS. The Canon had a better picture. At 400mm @ f/5.6 the Canon was noticeably better. It also costs more.

What is it about the 150-500 that you do not like? We are possibly talking small improvements here. Depending on your shooting those won't even show.

SVTmaniac wrote in post #15379392
Yeah that's what I meant. I'm all doped up on cold medicine right now. Thanks for helping me out.

Haha. No problem. I was scratching my head there.

I have and use a 50mm f/1.8 Mark-I which I will take any day over a new Mark-II lens.

I also have a 135mm f/2.8 soft focus lens which is one of the first EF lenses made.

I also shoot with older 300mm f/4L IS and 400mm f/5.6L lenses which are in great shape but which are older lenses.

Like previous posters mentioned, it is the amount of care and use that a lens gets, not the date of manufacture that matters. EXCEPT for lenses which are so old that Canon no longer services them such as the neat 80-200mm f.2.8L...

torkk wrote in post #15378845
Well, Im wondering is there a good year for certain models.

Like Bordeaux, I'd say 1961

Though seriously, I do wonder about the lenses produced shortly after the earthquake-tsunami in 2011. I wonder how much of an adverse effect that has had on precision optics production. Canon's Utsunomiya plant was forced to cease operations for a while afterwards.