From experience, 12-15 yr old wallpacks are great candidates for replacement. factor in the costs of bulbs, ballasts & labor, against the cost of a new fixture and labor.
You can order new fixtures (with lamps) direct from mfg like RUUD Ltg., or any of the other direct to contractor sellers. The MV bulbs are going to be 'unavailable' by Federal law either very soon, or possibly already. Pulse start MH provide equal light output at reduced input wattage, and new tech induction is a really great energy saver with incredable lamp life, but at a high $$$$ now.