This inquiry was triggered by the question What is the scrap value of wind renewables?.
The question essentially asks for the 'scrapping' part of the life cycle analysis of a wind turbine (a full LCA would include investigating alternatives like refurbishing, and would also take the contruction and usage into account).
Despite being limited to the 'scrapping part', trying to work this out is going to be broad.
There are more of these questions:
Do small portable solar chargers generate more energy than it costs to produce them?
How to determine whether hybrid cars are really more sustainable than traditional cars?
Whole-of-life impact of liquid soap vs solid bars of soap
Which is more sustainable: aluminium can, plastic bottle or glass bottle?
Which is more sustainable: Almond, Soy, Coconut, Cashew or Other Milk?
(Very often these would need several LCA's)
Answers are often limited: some other life-cycle aspects, it depends on ...
On the other hand, LCA is extremely valuable in the area of sustainability; personally I see answers to LCA questions as a major benefit for this site.
Yet I doubt that at the current stage/size we have enough people to come up with good LCA's - we're still beta ;-)
I can think of several ways to address these questions:
If they cannot be narrowed down sufficiently, be strict and vote to close as 'too broad'
Allow everyone to contribute whatever parts of the analysis (s)he can come up with; this often leads to questions with enough answers to satisfy the OP (given by an 'accepted' mark), despite not being a solid LCA.
(This seems to be the mode we're operating in now)
Steer the questions to "What aspects do I need to consider in the LCA of X?"
Steer the questions to asking for external resources
Thoughts? Any other approaches you see/want?
Note: We do have a life-cycle-analysis tag, currently used in 18 questions, among them: What are freely available tools or databases for Lifecycle Assesment?
Somewhat related question: How do you identify what is sustainable without reverting to lists and other people's ideas?