I just bought used Canon 24-105mm F4L IS USM lens. Lens is from 2005 can that 8 years has impact on sharpness or anything else. I'm wondering if i should buy newer. I saw 1 year old but $200-300 more. Thank you
IS USM Lens
Canon EF-S 18-55mm f/3.5-5.6 IS Lens
Canon EF-S 55-250...
Sharpness might be affected if there is anything like fungus inside the lens, the lens has been dropped or something similar. Normal usage should not affect the sharpness....but going for a newer one won't hurt :-) It's all about the glass :-)
If you are going to buy used, just be sure your seller has a rock-solid reputation. If you don't know your seller, or you don't have a way to investigate the reputation of the seller, it would be safer to buy new.
Used lenses can not only have fungus, as stated earlier, but also dust or scratches that could affect the quality of your photos.
That said, I have bought used lenses in the past and they have been fine, but I always made sure that I could trust the seller. It is worth the extra money to make sure you have a lens that has not been damaged.
Note: the passage of time alone will not affect the sharpness of the lens, but it has to be taken care of appropriately.