An "alarming" 80% of client assets are from the over-50s age group, according to research.
A CoreData survey of 1,260 advisers found the demographics of the market were amongst the biggest worries for advisers.
Optimism amongst IFAs is generally was improving, the research group said.
The rate of industry departures is slowing, with 9.6% of advisers expecting to be gone within five years, down from 14% in 2011. Three-quarters of advisers will continue to offer full independent advice after RDR is implemented.
That means advisers may not be in as short supply post-RDR as widely suspected, although the same may not be said for their client base, Craig Phillips, head of research for UK and Europe said.
"As more and more clients move into draw down phase and start chipping away at the children's inheritance, advisers will be forced to seek new client growth from the younger end of the spectrum to drive future value into their businesses."
The study suggests about 15% of advisers will offer restricted independent advice route, with the majority (73.8%) offering a full independent service. A small proportion of advisers (7.7%) are unsure what type of service they will offer after RDR, and fewer (1.4%) say they will be giving advice tied to a particular company.
The majority of advisers now claim to hold at least the basic level of qualification under RDR guidelines. Six in 10 (62%) advisers are competent to practice post-RDR, this is a considerable improvement from the 44% who were in this position last year.
Advisers are losing hope that grandfathering will be allowed after 2012 and have chosen to get qualified instead, Phillips said.
The chairman looks to inject some emotion into investing
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Charles Stanley pension business
A total of four acquisitions in 2017
GDP at 0.3% for Q1 2017