Advance warning this sizable is bound to encourage procrastination.
This time next year, the DSi Shop will go the way of the Nintendo Wi-Fi Connection service and cease to exist after March 31, 2017, Nintendo confirmed in a public announcement on the Japanese site. So in the next 365 days, check to see that you don't have neglected funds at the bottom of your digital wallet.
You can continue adding funds until September 30 of this year, after which point any unredeemed DSi Points can be refunded at a later date. Through what means, though, Nintendo has not yet revealed.
For the time being, you can still re-download games you have the license to via the DSi Shop — providing they haven't been taken down, of course. But once the service closes, that will no longer be possible. Best to pull down your collection now.
If the 3DS eShop has been your sole means of accessing DSiWare titles, then you have nothing to worry about as the digital storefront will continue to offer these titles for purchase. Good to know we're not preparing DSiWare's familiar favorites and many undiscovered gems for a permanent burial.
