Okay, time I see for an example from me (been a few posts between, so ya'll take a breather, and I'll make em short and sweet:
#1) had a PC, he got scragged in a jump-accident in char. generation! His daughters grew up. One became a pilot (played by my friend, I played the younger twin (by two minutes).
Well the GM moved, and we gottogether, and I got elected to lead off as GM.'kay? Then, I decided we take it "a few years since", retired off the younger twin to head up a starship firm at the B-class port the players frequented for fuel, and repair facilities. Some of them knew the original members of the group. My (now NPC) knew "every inch of their ship", but the new Players took a while to find that out (her married name threw off their early perception rolls.)
#2)A married couple of my gamers moved to Trenton NJ, early 95. What to do? they were central PCs in my plotlines... SO I got hold of em by phone, wrote down the pertinent stuff, and "retired them" out of RCES. She went "corporate running the "Salvage business", he entered politics on Aubaine, as a junior assemblyman, when his father's seat "came open due to health reasons."
For those who've scanned the BARD site, these were Winona "Bee-Witched" Yukowa, & Sean Lucky-Dice" Egan. Oh yeah, married them "offstage too for good measure.
These of course are examples of using PC- to-patron & PC to NPC background-contacts. Enjoyed it.
Next!