• Recency — “When was the last time I used this?”
• Frequency — “How often do I use this?”
• Acquisition Cost — “How difficult/expensive is it to get this?”
• Storage Cost — “How much space and maintenance cost is it tied to?”
• Retrieve Cost — “What costs are associated with retrieving it or it becoming outdated?”

R (Low) + F (Low) + AC (Low) +SC (High) + RC (High) = Not Worth It

...most people run into when trying to determine usefulness of an item:

• Exaggerating or over-emphasizing its need in the future.
• Underestimating the cost and space it takes up.
• Ignoring the storage cost.