To begin with, the base spirit loss for a death is 2 real-life days of play, each time you are forced to Spirit Walk.
So that means that if you are someone who dies very rarely, maybe once per month, and would have otherwise lived an average lifespan of approximately 12 months, then at the 11 month mark you would have shaved off approximately 22 days of play time, ending your character's lifespan. Put differently, someone who dies on average once per month can expect to live an average of 11 months without needing to buy a new Spark of Life.
Now, let's assume you die a bit more frequently, maybe once per week. Each death would shave off the same 2 days of play time. As a result, every 7 days would actually count as 9 days of play time. If you divide the average of 354 by 9, you get approx. 39 weeks. So if you're someone who dies an average of once per week, you can expect to live approximately 8.75 months without needing to buy a new Spark of Life.
Continuing on with the same model, if you died an average of 2 or 3 times per week, you could expect to live for either 7.25 months, or 6 months (rounded to the nearest week) respectively.
Now let's assume you die very frequently. You're out adventuring every day doing extremely dangerous activities. Every day you die once. That means every day counts as three days of play time. The average of 354 divided by 3 is 118 days. That's 16 weeks, or approximately 3.75 months before you need to buy a new Spark of Life.
