It depends on the application (I know, I know).
Most early DI engines only had DI, so there was nothing to keep the intake valves clean. This is where the focus on IVD started, because they were requiring periodic walnut blasting of the valves to clean them off. Work was put into determining how changing the oil chemistry could reduce the rate of build-up (it's still going to happen, just slower).
The more prominent issue with DI was when it was applied to smaller displacement turbocharged engines that were then "lugged" due to programming, which resulted in LSPI. The Euro marques hadn't had much issue with this, as their programming wasn't catering toward that sort of operating profile. This is where the focus on changing the amount of calcium in the additive package to mitigate LSPI happened.
Many recent DI implementations now use hybrid injection, that is, there's port injection alongside the DI. Toyota, FCA, Ford, I'm sure there are others. This prevents IVD's because of course the valves are being wash with the fuel mist like they are in standard port-injection only applications.
So, does your application have DI only, or is it a hybrid setup?