I cite below a scientific journal article, but let me reinforce it with life experience. My dad was in his 70's when his good friend was 82, a retired doctor (general practitioner in our small city, well known and respected) who had a HUGE growth on one foot but refused to let surgeons near it, as he said his many years of experience as a physician taught him that really old people often don't heal from surgery and he felt he had crossed the threshhold. (He died three years later, but it was because of a plane accident, he flying his own single-occupant little plane that crashed up the valley away from the city.) Then, having known him and his story, I recalled it when living with - as a boarder when a grad student - an 83-year-old landlord in a small apartment complex in Winnipeg. She was an oversized (yeah, fat) woman who had travelled the world, spent two years in China a ways back, and her slim identical twin sister was always worried about her. The thin twin pitied her "fat" sister in front of me, but I just smiled because I had had many conversations with her about her life when i was in the kitchen midweek preparing my meals and the so-called "fat" twin felt her sister was too society-conscious and had never left Winnipeg and seen the world and was narrow minded. Anyways,... that oversized landlord I rented a room from had to have appendix surgery, according to her doctor, and she had to decide whether to have it right after Thanksgiving in time to recover for Christmas with the grandchildren (she was a widow) or whether to wait and have Christmas with them and have the surgery the week after. The surgeon urged an earlier date, but I remembered my dad's doctor friend's wisdom and suggested she wait. I didn't argue for it, mind you, and the that fact haunts me a little, as, you see, she had the surgery to remove her inflammed appendix, and it was declared a victory, but her body didn't heal and the stitches didn't remain closed and after three-plus weeks of the doctors trying to reclose their own incisions, the woman passed away from blood loss, all the while in the hospital, it being a few weeks before Christmas, she didn't get to see her grandchildren again as she so hoped to.

Wound healing and aging.
Gerstein AD1, Phillips TJ, Rogers GS, Gilchrest BA.
Age-related differences in wound healing have been clearly documented. Although the elderly can heal most wounds, they have a slower healing process, and all phases of wound healing are affected. The inflammatory response is decreased or delayed, as is the proliferative response. Remodeling occurs, but to a lesser degree, and the collagen formed is qualitatively different. Diseases that affect wound healing are more prevalent in the elderly and have a greater adverse effect on healing than in young adults. Thus, particularly in the elderly, concomitant medical problems should be treated vigorously to allow for maximum healing. Recent trials of novel therapies to enhance wound healing suggest, however, that much can be done to improve the prognosis of elderly patients with risk factors known to adversely affect wound healing.

I talk about this now because I'm pushing 50 and a wound from last spring still hasn't totally healed, to my surprise (it's just a friggin' cat scratch on my hand between the thumb and fore finger, but it's now a scar, having refused to close entirely smoothly like every other cut I've ever had.