How long do shock absorbers last?

Hello all, my V70 II is currently in the Volvo workshop wg. grim suspension noise from the rear part of the vehicle. Diagnosis of the workshop: both rear shock absorbers have to be replaced. Before I get upset about it now, the short question whether it is normal that shock absorbers are worn after 100,000 km or 5 years respectively? Never have my car been heavily loaded and drive completely moderate. The shock absorbers on my 12 year old Audi are still impeccable (have I I’d like to hear from you about your experiences.