When will the future arrive? When does the nifty new science you read about in the popular press turn up in the clinic? When will the new medical technology be reliable and widespread in availability? I've found the best way to think about these sorts of things is to play a speculative game of counting development cycles.
It takes a certain amount of time to move from proof of concept to fundraising to development to commercialization of an actual product in fields dependent on scientific research. Much of this time has to do with human organization, communication and collaboration, rather than the actual work of progress. Even in the least regulated of such fields, a five year turn around is not unreasonable. Only after five years will the first widespread feedback, adaptation and planning begin for the next iteration of the broad, competitive development cycle.
It's important to realize that large differences in timing exist between what is theoretically possible, the expected dates on which a funded scientific community can deliver technology demonstrations, and availability of a commercial product. This is especially true when government regulation is involved in the process.
But on to the estimations. My view of the biotech and medical research field suggests that the development cycle for new products medians out at around a decade - a far cry from the rate of advance possible in less regulated industries, such as the development of computing devices. Calorie restriction mimetics look to come in under that median, while gene therapy is lagging far behind. Applications of autologous stem cell therapies look to fall somewhere in between. There are plenty of other examples if you care to go digging.
The conservative late adopter waits for the second business cycle for any product he can afford to wait for. The second round is always better than the first, more effective, cheaper and more widely available.
So to pick an example: I believe the estimates of the late 2010s for the first commercial organ generation via tissue engineering. That seems plausible, given progress to date; the first technology demonstrations are still a couple of years away, pending solution of the blood vessel problem. That suggests that the late 2020s would the time of routine, widely available organ replacement - a procedure analogous to preventative surgery today - at the completion of the second development cycle.
Another example: replacement of all damaged mitochondrial DNA through one or other of the vectors presently demonstrated. Should one of these research groups obtain sufficient funding, they will enter the ten year track - but it might take years more to arrive at that point. It can't hurt to assume that any promising, generally unfunded science is at least five years away from building critical mass. For that reason, I think the early 2020s are the earliest we are likely to see commercially developed mitochondrial DNA replacement technologies.
Following the two cycle rule again, that means the early 2030s will be age of routine mitochondrial DNA replacement starting in late middle age, an outpatient procedure that your physician will badger you into doing every couple of years. It'll be a pain to schedule, like the biopsies and exams, but skipping it will be like not checking for cancer - just dumb.