You can fix most common office furniture problems, like stuck drawers, by examining the problem and applying a simple solution.
If your desk chair has difficulty rolling, turn it upside down and examine the wheels. There could be a small pebble or another object stuck to one of the wheels. Remove object and clean all wheels. If there are threads or hair entangled in the wheel, remove foreign objects and wash thoroughly, turning the wheel as you do so. Some office chairs have the wheels which just pull off and make it much easier to clean them. Sometimes the foreign object isn't visible until the wheels are removed. Also clean the inside of the chair leg where the wheel attaches. After cleaning, spray lubricant onto the wheel rod, and into the wheel rod hole to keep wheels turning properly. Dry thoroughly before re-assembling. Other chair problems could involve the adjustable back, which might keep coming loose. Depending upon how the chair is made, tighten the bolt or turnstile which holds the back. To keep it from loosening again, spray with a lock-tight spray which prevents the nut and bolt from turning easily. If the back is stuck in one position and you want to loosen it, try spraying lubricant on the bolt assembly. If the bolt or nut is stripped, these will have to be replaced. If your chair seat seems lumpy, turn upside down to check for broken springs. If there is a dust cloth on the bottom, it can removed for easier examination, then replaced with a few staples. If there is a broken spring, the chair will need to be fixed or replaced. If a sofa, chair or love seat which is reserved for your clients has a broken leg, you will probably need to have it replaced, but if the furniture has other problems, like the cushions are getting where they sink too low, or lose their shape, simply replace the interior foam. Unzip the cushion, remove the old foam and take it to a foam retailer. They will cut the pieces for you and you can just slide the new foam into the cover. If it's hard to slide back in, try spraying it with some silicone spray. If the arms of the client furniture are seeming worn, you can sew arm covers which are of a contrasting color, rather than replacing the furniture.
File cabinet drawers which are hard to open can also be sprayed or rubbed with a type of lubricant, but if that doesn't seem to help, check the rails that the drawer slides across. Maybe they're bent and can easily be bent back into shape. If that's not the case, check to see that a small piece of paper hasn't gotten stuck into the slide. If again that's not the case, clean inside the slide with a toothbrush and water, then dry thoroughly with paper towels. Also clean the drawer bottom itself, in the area that slides into the cabinet. If there is rust visible in the slides, you'll need to clean the slides with a rust remover, then spray with a rust prevention treatment, and after drying, lubricate well. For keyboard trays, the same methods are used. If they are slow to slide, or they stick, check the slides for foreign objects, clean and lubricate. Office furniture is expensive, so why replace it if you can fix it yourself? Before purchasing a new piece, examine it to see if you can fix it yourself, and if not, hiring someone to fix it is usually still cheaper than purchasing a new piece.
