USA Do I need to amend prior returns if I don't care about the loss?

[notataxexpert]

My husband has been a part of an LLC that owned rental properties. Through our 2012 return, he was responsible for taxes and we would get our K1 and include the info on our individual return. At that time we were carrying forward an 18K passive loss. The tax responsibility then passed to another member and we received our K1s so late each year that we started filing our individual returns without the schedule to carry forward our basis/unrealized losses in the LLC. We figured we would just worry about it later since it didn't have an impact on our return. Last month, the last property was sold and the LLC is no longer, so we will receive a final K-1. I think it would cost more to amend our prior returns than any net dollar we might receive from the loss on the LLC. We don't have other passive activity to offset. Can I just choose to not report a loss and not include the information in our return? I think if this year's K1 were to show a gain, I would need to go back and amend to keep the loss moving forward to offset the gain, but would I have to amend every year between 2012 and 2017, or could I just amend last year to reconcile against this year? Appreciate any advice someone might have on this.