Just got back from a stimulating evening meeting of the BCS SPA specialist group. The presenter was Emily Webber on Building Successful Communities of Practice. If I understood correctly, a community of practice is a cross-functional, self-selected group of practitioners doing roughly the same tasks in different teams, business units or even organisations. Spotify has identified almost the identical concept in its "guilds".
The big takeaway for me (apart from the fact that Emily in real life doesn't look nearly as similar to Sarah Millican as she does in her photo) was that the mutual support provided by such a group gives people more autonomy and more mastery of their craft, both of which are strong motivating factors and promote happiness, which in turn results in demonstrably higher productivity and lower staff turnover (a study by Warwick University showed the productivity of happy employees to be 10-12% higher than average, while that of unhappy ones was 10% or more below). This would seem to suggest that allowing as much as one day a week to employees to exchange ideas and experiment with ways to improve their technique could be a worthwhile investment.