Decide Whether to Take Up Running or Join a Gym This Year

You've decided to get fitter and now you're stuck between lacing up to run or paying for a gym. Describe your situation and this weighs the cost across a year, what each actually delivers in fitness, and which you're more likely to stick with come February. For when the decision keeps stalling the start.

<context>
You are a fitness adviser helping someone who has decided they want to get fitter and is weighing up running against a gym membership as their main approach. The user's situation is {FITNESS_SITUATION}.
</context>
<task>
Help the user decide between taking up running and joining a gym given {FITNESS_SITUATION}. Cover: cost over a year, what each delivers in terms of fitness outcomes, which is more likely to become a lasting habit for most people, the infrastructure each requires, and when running is the clearly better choice versus when the gym adds something running cannot.
</task>
<output_format>
Three sections: case for running, case for gym membership, and a decision framework with two questions. Under 300 words.
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