Hostels cluster in two kinds of areas, and it's worth knowing which you're booking. Many sit in central, nightlife-adjacent districts, which are lively and convenient but can be rowdy at 3am and occasionally sketchy at the edges; others land in cheaper neighborhoods a bit out of the center, where the trade-off is a quieter street but a longer walk home at night. Neither is automatically unsafe; the question is whether the specific block suits how you travel.
Researching before booking takes ten minutes. Drop the address into a map and street-level imagery and look at the actual block: lighting, shops, how the neighboring buildings look. Read recent reviews specifically for the words neighborhood, area, at night, and walk, because guests write candidly about feeling unsafe walking back.
After arrival, ask staff which streets to avoid at night; they answer honestly because their guests' safety is their reviews.