For a single truck, a local distributor with stock, because lead time matters more than the unit price. For a fleet, factory-direct against a written specification covering voltage, amp-hours, BMS rating, footprint and charger. Compare landed cost, not just the unit price.

Rarely. A used pack has unknown watering history and most of its cycle life already spent, and used packs are often sold precisely because capacity has started to fall. If you do buy used, load-test every cell and buy the whole string out of one truck rather than mixing sources.

Repair is defensible when one cell or connector has failed in an otherwise healthy, recent pack. Once capacity has fallen across the string, repair money goes into a pack that will still need replacing, and the downtime cost usually settles the argument.

It depends on voltage, capacity and chemistry. A lead-acid pack for a standard counterbalance truck sits in the low thousands; a lithium pack of equivalent usable capacity costs more up front and less per shift once the battery changes and the charging room are removed.

Voltage, amp-hours at the stated rate, plate or cell construction, BMS continuous current rating for lithium, compartment dimensions and terminal layout, charger specification, warranty terms with the pro-rating schedule, and lead time. A quote missing any of those is not comparable.