For me personally I like the R&D option, however in smaller teams with timelines it always leads to being scrapped because project X needs to be delivered by Y.

For me personally I like the R&D option, however in smaller teams with timelines it always leads to being scrapped because project X needs to be delivered by Y. A note to employers around this, let the developer choose the project - even if it has to be relate-able to the company in some way. If it's a big company I'd love to go to other areas of the company, meet people in other areas of work and ask them about their work flow, problems they encounter day-to-day and if it's interesting and tech-solvable - build a solution! Or if your devs aren't as "go-get-em" as I appear to be, offer a few examples that you've researched and offer them the opportunity to do the above.