Before the rats arrive, have all of this ready: Cage: wide, multi-level, correct bar spacing, deep base, solid shelves. Set up and positioned already. Bedding and substrate: paper-based bedding or kiln-dried aspen for the base, plus soft nesting material - unscented toilet paper, ripped paper, or fleece strips. No pine or cedar shavings, no cotton-wool style fluff (it wraps around limbs). Sleeping: at least one hammock per rat plus a covered hide or two. Rats sleep in a pile but like options. Food and water: a base mix or blocks, a bottle with a working ball bearing, plus a heavy backup bowl. Litter: a corner tray and a different, obvious litter such as paper pellets. Rats often litter train themselves if the tray is where they already go. Enrichment day one: cardboard boxes, a tube or two, a rope or hanging toy, a dig box, and a foraging tray. Handling kit: a small carrier for vet trips, a set of digital kitchen scales, and a notebook or the Infirmary here for weights and health notes. Cleaning: a rodent-safe disinfectant (F10 or similar), white vinegar for scale, and a spare set of fleece so cleaning day is quick. Money: your vet's details and a small emergency fund. This is the item people skip and regret.