Just remember - they do not have a lifetime warrenty - they have a "Satisfaction Guarantee".
Ask yourself:
Am I satisfied with the purchase? Did I get what I paid for? Did it meet or exceed my expectations?
If I buy a pair of shoes at LL Bean that costs me 3x a pair at
Walmart, I would expect them to last approx. 3x as long. I expect walmart shoes to last a few months - I therefore expect LL Bean shoes to last me just about a year. If they have lasted me that long, then they met my expectations and I should be satisfied. If, however, after a few months they wear out, yea, I'd exchange them.
I would, however, be responsible for the cost of shipping the item back to them (unless of course if I was an LL Bean Visa card holder, then return shipping is free - not sure if this applies without receipt or not though).
You say you had an item for a "few years" - what was the item, and how long did you expect it to last. No matter WHERE you buy an item, after a "few years" an item will be worn, no matter what the item is.
I say all this as a former employee of LL Bean, so I am very familiar with their satisfaction guarantee.