I don't think Pierce would retire this year. He's banged up right now, but he still has a lot of basketball in him.
As for KG, he "could" see him retiring at the end of the season except for one thing...
Pierce: "KG, I need you to play one more season with me, maybe two".
KG: "Nah, I'm done".
Pierce: "KG, we've been down the road together for 5 years. I "need" you at my back.
KG: "Ok, I'm in".
KG's too loyal in the best sense of the word. If his teammate that has battled with him for 5 years asked him to play another year or two, KG won't turn him down.
Bank on that and bank on Boston at a discount - there is absolutely "ZERO" chance KG goes elsewhere in free agency.
Zero...