The essential idea is watching your resource cycles carefully since everything needs to connect for true indefinite survival. When you start, focus on securing a mag lens first, it's basically your forever fire starter once you master the timing - look for clear skies between 10am and 2pm for optimal use. Your main threats come from the initial equipment degradation phase where you'll need to transition hard into crafted gear. Speaking of gear, wolf and deer populations respawn infinitely so focus your early hunting near sheltered areas where you can process hides safely

Players pushing past day 1000 follow strict routines especially on interloper where the timing of your daily activities becomes critical. Maybe interesting: you can actually maintain tools forever through beachcombing for metal, just time your runs with aurora forecasts. The real sustainability comes from stacking your tasks - use sunny days for both fire starting and hide curing, cook in bulk when you have good weather, and always cure multiple hides at once

The biggest threat to long-term survival isn't actually the cold or predators, it's getting caught in bad resource cycles. Stay ahead on your hide curing, maintain at least two sets of crafted clothes, and keep your tool repairs regular. Some players have pushed well past 10000 days using these systems though it definitely takes some serious dedication to the daily grind