Advisers should create a panel of platforms, with a different one for each client segment, according to analysis by the Lang Cat.
The Edinburgh-based consultancy firm conducted a due diligence exercise with a fake financial advice firm as part of its latest Platform Market Scorecard report.
Its research highlighted the "increasing difficulties" of a single platform being suitable for every client on an advice firm's books.
A solution of having a small number of platforms for each client segment - for example depending on the level of assets the client had - would also address the difficulty of assessing each of the 20-odd platforms in the market for every client.
Steven Nelson, head of research at the Lang Cat, said: "Due diligence remains a key issue for everyone in the sector, whether you’re a platform or an adviser.
"With 20-plus intermediated platforms to choose from, it’s impossible and impractical for advisory firms to assess each one for every client. Yet many tools and adviser services are set up to encourage this very way of working.
"There needs to be a robust and defensible process of creating a manageable panel that meets client and adviser requirements but is also realistically priced for what it does. Cheapest does not mean best, something cheap and unsuitable is still unsuitable."
The analysis the Lang Cat did with its fake financial advice firm - called the Long Dog, based on having 40 clients with average model portfolios of £350,000 and all but one with a moderate to high weighting in a pension wrapper - showed some platforms were better for clients with different levels of assets.
First, the company whittled all platforms on the market down to a longlist of seven based on their technology, functionality, products and tools, before assessing their charges.
For example based on platform charges the Lang Cat found Nucleus or Elevate would be better options for more modest portfolio sizes, Transact and Zurich were better for medium-sized multi-wrapper portfolios but AJ Bell was a more natural option for medium-to-high sized portfolios.
Based on its analysis, the Lang Cat came to the conclusion it would be "ludicrous" to assess each client on price against each platform, but advisers felt under pressure to do so.
It recommended creating a "strategic platform panel" after carrying out proposition suitability first, so clients would naturally fit into one of the platforms, but it warned against this becoming a "reflexive" choice.
Mr Nelson added that Mifid II product governance rules (PROD), which came into effect in January, highlighted the importance of advisers segmenting their clients.
The product governance rules of Mifid II include requirements that manufacturers and distributors of products get to know their target markets.
This means advisers will have to consider which target market a product is likely to be suitable for, have a distribution strategy for their target market and review the products they offer regularly.