Some vehicles are simply just so rare that to restore them would be the wrong thing to do. Guessing the original Bugatti that surfaced a couple years ago in England will never be restored, but lovingly reconditioned, probably with at the most some minor refurbishing. Guessing Vic's 443 mile 6xxx sandcast had, at the least, some minor patina that appeared over time, since leaving the show room, yet in such fine condition to command the price it did and to recondition, refurbish or restore anything on that bike, would be in my eyes, an outright and flatly wrong. (to my way of thinking that bike is not meant to be ridden ever.)
Then, there is #97....... Without being restored, not alot to enjoy in it's as is or refurbished condition, save the transient thrill of the initial aquisition. Same for 232, 576 or 4363; all rollers and with missing or damaged parts, making no ssense dollar and enjoyment wise to leave in as is condition or try to refurbish. To restore or not restore is a decision the owner will make. Probably sometimes when restoring a vehicle, restoration may not have been the best thing to carry out, having been better to leave things mostly "as is" with some thoughtful reconditioning or refurbishing...... ?
With 2157, it will be a bit of what i call a bastard combination of reconditioning, refurbishing and restoration. Sans toolkit, sidecovers, airbox, oil tank, exhaust and engine, the bike was complete, correct and original, right down to both mirrors. Came with nearly 4 decades of layered on scum, but mercifully, no rust or corrosion. Dismantled and carefully cleaned EVERYTHING. Replaced old with new wheel bearings, seals, tires, chain, etc. Black frame paint had numerous scratches, so out with the paint pen, followed by careful polishing with paint rubbing compound. Some of the engine mount brackets, NO paint, so out with the single stage black spray rattle paint can. I replaced sidecovers w/ Yamiya, airbox DSS, oil tank and tool kit Ebay. Replaced all the perishable small rubber ancillaries. E2241 cases came from a fellow member and building the engine using parts from other engines. None of the covers will be polished. The cases I've repainted (a first for me...) New Yamiya seat cover and my local upholsterer's foam with original red foam to cover the seat pan breathing holes. New Candy Blue-Green paint from the local painter. New HM30's. Overall, and from 5 feet, bike'll be looking pretty damn good and will have NO hesitation getting the thing wet or rained on or leaving it sitting in the sun all day while at work........ The gauges are original, the "red zone" is green, but i have replacement dial faces, from our Brother LeCram. Should the fateful day of restoration ever come, which is likely doubtful, I'll just ride and enjoy 2157/E2241 until then.