Don't sell and buy again! Just keep the lipos at storage charge. Check on them once a month. I had kept mine in storage charge for 6 months. Periodically checked them and topped them off to storage voltage if needed. Took them out for some serious run time past few weeks and no issues, no swelling etc .... running as expected.
I'm not a serious racer so I'm not concerned about having the most fresh packs etc etc ...