Stipulations:
- You cannot die and are immune to disease
- You cannot alter the future such that you change the world from your point of origin. i.e. You cannot become so famous that future people recognize you as immortal.
- If you vary the timeline too much you will cease to exist.
I think if I was 20 I could just backpack all over, get easy cash in hand jobs and fuck around for decades. However, if I’m sent back now at 48 being twice the weight I was at 20 I’d probably struggle as this late middle-aged oddball who has come from nowhere and has no period-specific skills.