At optimal speed, you get your items back in 174.5 days. You could ostensibly reach level 28 (174.5/(6+10/24)=~27.2, with the first two levels being fast, that’s 28) without burning anything, even if you get everything right.
174.5 days as in:
| Current Item Stage | Next Item Stage | Time until next transition |
|---|---|---|
| Apprentice 1 | Apprentice 2 | 4 hours |
| Apprentice 2 | Apprentice 3 | 8 hours |
| Apprentice 3 | Apprentice 4 | 1 day - 1 hour |
| Apprentice 4 | Guru 1 | 2 days - 1 hour |
| Guru 1 | Guru 2 | 1 week - 1 hour |
| Guru 2 | Master | 2 weeks - 1 hour |
| Master | Enlightened | 1 month - 1 hour |
| Enlightened | Burned | 4 months - 1 hour |