I knocked up a front deck a few months ago, to replace and extend a crappy old one that was rotting and falling apart. It's 6.2 x 3.8m so not huge but it's made a world of difference to usable outdoor space for dining etc. It was complicated by the original house foundations being poured to allow for a porch outside the front door (which I've removed and filled in the alcove for more interior room) so I had to set in some 2x4s to nail the deck into over top of the foundation. This set the height for the rest of the deck and was a pain to get a fall away from the house for water run-off.
We've also got about 110sq.m of vege and berry gardens out the back, which I've been boxing up over time. Some of it is just rough while some of it is more permanent, with merchant-grade decking used for the sides and polythene lining to prevent rot and chemical leeching. I've fitted an irrigation system around the inside of the boxing of the largest gardens and run lines to all the gardens, and fitted a water computer to handle the whole system, so it's set and forget. It grates me every time I look out the back that I've refined my technique with each garden so they range from pathetic to mildly acceptable.
I've also fitted a valve and outlet to the two main gardens that will enable me to run irrigation hoses down into the reserve behind our property to water plants there as well.
We also have a 2.4m x 1.8m greenhouse as a nursery, plus an outdoor nursery where we grow plants to put in the reserve and for our rental properties.
I still have to rebuild the old shed so I bought a couple of zincalum kitset sheds to store everything while I pull it down. I also have to build a pergola out the back too. Always something else to do...