Why 2 to 5 percent is the number
Spare parts are priced on attrition, not on pessimism. Across a 150 cover room fitted with 120 restaurant chairs, the parts that fail annually are glides at 5 to 8 percent, fixings at 2 to 3 percent, and seat pads at 1.5 to 2 percent in a room running four turns a day. Ordering 3 percent of the chair count as complete spare chairs covers the structural losses, and ordering the small parts at 5 to 8 percent of positions covers the wear items. On a 120 chair order that is 4 spare chairs, 8 sets of glides and a box of fixings.
The alternative is a mid-service purchase. One chair ordered as a one-off in month 14 carries full unit price plus a separate freight booking, and in most quotation structures that lands at 2.5 to 3 times the per-unit price paid inside the container. The same chair ordered as a spare inside the original order costs the unit price and 0.7 cubic metres of container space that is usually available anyway.
There is a second reason that has nothing to do with cost. Colour and finish are matched to a production batch. Replacements built 18 months later from a different batch of powder coat or a different lot of leather will be visibly different beside their neighbours, and no factory will guarantee a match across a gap that long. Spares from the same run are the only reliable way to keep a room looking like one order.
What is worth stocking, part by part
Glides come first, and there are two specs that decide how many you need. On a timber leg, a 12 mm stem glide lasts 18 to 24 months on a hard floor; on a stacking frame, a 10 mm plug glide lasts 12 to 18 months and is lost more often because it pulls out. Order two full sets per 40 chairs, plus the correct extraction tool, which costs less than a wasted hour of labour per chair.
Fixings come second. Most commercial chairs use M6 bolts at the corner blocks and M8 at a table base plate, in zinc plated or stainless grade. One box of 200 of each, with the matching hex key and a torque figure written on the lid, is a 30 dollar line that saves a service call. Count the fixings on one chair during the first assembly and multiply: a four leg table with a plate base has 16 fasteners, and a bolted chair has 8 to 12.
Seat pads and upholstery come third. One spare seat pad per 25 chairs in the most used fabric, and 2 square metres of the matching upholstery for a booth run. On restaurant seating booths this matters more than on loose chairs, because a damaged booth panel cannot be swapped for a chair from the store room and the whole banquette reads as worn once one panel is different. Touch-up paint matched to the RAL or the stain code, and a tin of the exact PU lacquer sheen, complete the small parts list.
What is not worth stocking
Complete frames are the obvious trap: a bare frame without its upholstery is not usable and takes the same floor space as a chair. Buy complete spare chairs at 3 percent and stop there. Welded bases for tables are worth exactly one spare per 30 tables only if the base is a stock item; if it is a custom fabrication, a spare base is cheaper as a drawing than as inventory, because the factory can rebuild it from the file.
Upholstery rolls are the second trap. Two metres is useful, 20 metres is capital sitting in a cupboard and going out of fashion. The exception is a booth run in a fabric with a 20 day lead time from a mill, where the risk of a discontinued colour justifies a full panel length.
Veneer and stone tops are the third. Spares in a matched veneer will not match after two years of light exposure, and a slab top is heavy enough to need a proper rack. Better to hold a repair budget and a relationship with a local refinisher than to warehouse a top that may never be needed. The same logic applies to restaurant tables in general: stock the fasteners and the base, not the top.
The parts that fail on a schedule
Wear in commercial furniture is predictable enough to plan against. Glides go at 18 to 24 months on tile and at 30 to 36 months on timber. Bolted joints loosen after 8,000 to 12,000 sit-and-stand cycles, which in a four turn room is about 30 months, and the symptom is a wobble that gets blamed on an uneven floor for six months before anyone checks the bolts. Foam at 35 kg per cubic metre loses 8 to 12 percent of its height in three years under daily use, and the cover then looks loose before it looks worn.
Powder coated frames chip at the contact points and at the glide seat. Those chips are the only place a steel frame will rust in a dry interior, and a touch-up pen applied within a week stops it. Leave it a season and the chip has a brown halo that no pen will hide.
On JP-C002 metal dining chair the parts that wear are the glide, the four seat bolts and the weld at the rear leg. We ship a spare kit with chairs of this construction when asked, and the kit is the wear list above rather than a random selection: four glides, four bolts, one touch-up pen. The same logic applies to any model, which is why the spare list should be built from the bill of materials rather than from the accessory catalogue.
Writing spares into the purchase order
Spares only arrive if they are a line item. Put 4 spare chairs on a line with the model, the finish and the upholstery batch, and they get packed, because the line is priced and counted. Left as a sentence in an email, spare glides become whatever is in the packing bin that afternoon, usually nothing.
Three clauses do the work. First, quantity: 3 percent of chair count as complete units, 5 percent of positions as glide sets, 200 fixings per model. Second, identity: spares tagged with the model number and the finish code, in the master carton of the last pallet, with a packing list that names them. Third, support: a written commitment to supply parts for 5 years from delivery, with the drawing or the part number held on file.
Ask for that third clause before the order is placed, not after. The factory that builds your custom restaurant furniture to a drawing can always remake a part from the file; a trading company that bought the container from someone else cannot, and the difference only surfaces in year three. If the supplier cannot name the part numbers on the drawing, the five year commitment is not worth the paper it is printed on.
Budget the whole line at 1.5 to 2.5 percent of the furniture value. On a 60,000 dollar package that is 900 to 1,500 dollars, which is less than one emergency freight booking and covers roughly the first three years of wear. Put it in the opening budget rather than the maintenance budget, because maintenance budgets get cut in the first quarter and opening budgets do not.
Storage and tracking, in 0.4 square metres
Spares that cannot be found are not spares. One shelf 900 mm wide and 450 mm deep holds the whole kit for a 120 cover room: two labelled bins per model for glides and fixings, one bin for touch-up, seat pads stacked flat above. Label by model number and finish code, not by description, because a bin marked glides will accumulate three incompatible types within a year.
Track two numbers monthly: glide stock and bolt stock. When either falls below 20 percent of the opening quantity, reorder against the part number rather than waiting for a failure, because the failure will arrive during a Saturday service. Five minutes at the monthly walk round is the whole system.
The last piece is the person. One named member of staff, usually the maintenance lead, owns the shelf and the reorder point, and the drawing file sits with the spare list so a part can be identified without calling the supplier. On the packages we ship from our workshop, the restaurant furniture manufacturer side of this is a parts list on the last page of the packing documents. The room side of it is a shelf and a name.