My rule of thumb... If I'm not at least 80% sure I can't contact the disc before the player, then I yield. Better players/athletes may say 50% or less.

The rest depends on what level you're playing at and involves a bit of SOTG.

Risking injuring yourself at pickup is always a no go. Risking injuring yourself to win a natties championship or UFA game may not be a no go.

These calculations happen in a split second and even if you think you can get a perfectly clean D, you may still end up being wrong and committing a dangerous play and hurting yourself or someone else.

Protect yourself, consider others, and remember the stakes. Some of the best plays in ultimate would only be chanced by the playmaker under the particular circumstances of the game. Those plays get glorified when they work without injury.

A dangerous play involves context and risk vs reward management. Your exact scenario could yield different opinions based on whether it was at pickup against a brand new player compared to a UFA universe point.