I had my first cx5 8 years, never failed mot, driven for hundreds of miles thru harsh scottish winters ( passing dozens of gritters ) if you do your best to keep clean it will last longer, i would be more concerned with the body paint over underbody tbh, you say several years if thats below 8 then i wouldnt let that concern you. Also the last 3 years of ownership i ran that car like a works van and thats why i ended up replacing it with the 2020 model.