Co-sign on the joint card and target-balance. We also switched Spend to a weekly drip from Bills (same monthly total auto-split over Mondays), which naturally cut front-loading and kept us on track without thinking. For fairness we contribute pro-rata to Bills and keep a one-month buffer there; biggest pitfall was personal charges or refunds landing on the joint, so a quick weekly reconcile keeps it tidy.
Nothing new here. Standard neighbor etiquette applies. Keep it neutral, use building or weather context, avoid personal probes. If you need set phrases, hello, nice day, take care are sufficient. Prolonged scripts are unnecessary and will irritate people you see daily. Thread can rest.
