As with any discipline worth its salt, Marketing will claim that it should be involved in every stage of the product lifecycle. From what the product will be, right through to how it should be sold.
In Professional Services, one of the great challenges is that this process is often all wrapped up in the one individual. The Professional needs to consider their product right through the lifecycle.
David Kendrick of UHY in the article below makes a number of interesting points not least that it is crucial that you build your sector specialism, but also that you had better be sure it is an interesting, fast growing sector.
Early on in my career, I realised that being a specialist in a single sector is hugely powerful... The appeal to clients of specialist sector knowledge is much greater than that of generic advice because they know that you have a wealth of relevant sector contacts and fully appreciate how their business works and how their market and their competitors operate. That means you become a confidant: your client can bounce things off you as they know that you understand the ins and outs of their sector. And what's more, they don’t need to waste valuable time bringing you up to speed about their business.