The '126' is IMHO, the BEST EVER BUILT. However, the rubbery 'undercoating' can crack or get torn, or water find its way through a panel form the other side--and terminal rust cancer can kill the car--especially the passenger side firewall and front bottom of each rear wheel-well.

Inspect the lower front passenger firewall and all other areas at least once a year and faithfully clean-out and repair ANY cracks or tears in the coating. Rust is VERY hard to detect under the rough coating. Some other models have front upper spring perches falling off due to rust at the perch/frame(body) joint hidden under the 'rustproof' rubbery coating. Same issue around rear window, rear door quarter windows, under door gaskets, trunk gasket, inside bottom edge of trunk lid,etc. All the crevices MUST be kept clean, dry, and rusp proofef. LPS #3 is BY FAR, the best after-market rust preventive for inside seams and body cavities. (I kept a 1971 Chevrolet VEGA ( a well proven rust bait) RUST FREE for over 15 years in a highly corrosive industrial environment by LPS#3 sprayed into all areas and seams (took out ALL screws and bolts, exterior and interior that penetrated body panels and cavities, foamed/sprayed generously with LPS#3 aerosol cans). Result was a quieter, absolutely rust free car.

Remember, the 126 'frame' is thin sheet metal formed into complex shapes, and only a little rust is needed to greatly weaken the structure.