990SD rear shock at 35k miles

Possibly but mine are approaching 80k miles and feel fine to me.

I have had front and rear bouncy bits serviced every 10,000, for me there is a notable and marked difference before and after. IMO worth the time, effort and money to get serviced /sorted every 10,000 miles. Having said that, North Yorkshire roads do give the bouncy bits something to do.

my shock seal was blown by 29k miles.....

you definitely want to refresh the fluid/gas by 35k

Mine blew at 12k when I was on track, shock oil all over the rear of the bike isn't recommended.