Should I have a bone graft upon #2 extraction in anticipation of implant years later?

I need molar #2 (root canaled 18 years ago) removed, there is a cavity below the gum line that has or soon will pierce to the gutta-percha. There is a gap between #2 and #3 which encouraged the rot of #2 and threatens #3, so I need #2 removed soon. I think the bone structure is good. Will I save money or better my long-term prognosis by paying for a bone graft now (upon removal) vs. immediately prior to implant? Assuming 3 years between removal and implant work.