I feel like some of this is at the discretion of each region. While there are certain refreshes that are clearly centrally mandated (1999, 2008, 2013, 2019), others feel like they are taken by each region. Some English regions, for instance, have had far more sets than others - some have only had two sets since 1999 (usually through refreshing the hell out of the 1999 one) while others have had four. If some of these rebrands are 'non-essential' then they presumably come out of the region's budgets and some may choose to spend their money on non-cosmetic things. It would be great to get an insider's take on this.
Full disclaimer; not an insider.
However it was alluded to on here that (outside of capital expenditure projects like The Forum, Birmingham, Salford or Plymouth moves and refurbs, or corporate mandated changes) set changes and refreshes come out of local budgets.
Nottingham for instance had a change in 1999 to the corporate look, then a new set in 2004 (Which was refreshed until with new set dressings/paint until recently it was refitted). Others got sets to match
N6 from 2008 until 2010. This would have come from the programme budget to replace legacy hardware that is either not as efficient or not manufactured anymore.
Birmingham had the same core set (aside a refresh in 2010) for 6 years, with many components of that set surviving 7 years moving with them from Pebble Mill. Then two complete refits in 4/5 years (recycling the same rostrum). Again this was out of the programme budget; the 2017 set (which curiously uses a square rostrum) was down to a lack of versatility with the set installed in 2012 (with a massive desk and limited camera angles) - this meant the political programming always looked awkward as the furniture was too low. The parts from the old set were redeployed, the screens being used in the Mailbox for alternative presentation, office use - some even got sent to Scotland I'm led to believe for PQ to make use of. The new set is able to be lit and dressed more easily for the odd regional programme they now produce. The downside is now Politics England is a thing the set lighting is rarely changed from the base colours of red and white... a shame.
.
