A big interest of mine is warship design and models. After a childhood of 1/600 Airfix plastic models and some 1/1200 original Triangs, given to me by a favourite uncle, this lapsed for many years then I realised I could afford the definitive reference books (Friedman; Raven and Roberts; Burt; Grove...) and discovered the world of 1/1200 and 1/1250 waterline models. Since then I have built up a bit of a collection, mostly focussing on Royal Navy ships of WW2 and after.
One I recently bought on Ebay was a Delphin model of a Type 81 frigate. I carelessly broke the mast off and one bit of restoration led to another so I ended up completely stripping it, remodelling the 4.5" guns, adding a lot of detail and repainting. Bear in mind this is 88 mm long.
The one part that is very unsatisfactory on this (and all other late WW2-1960s RN) ship is the mast - a solid casting just doesn't represent the characteristic scaffold-like masts very well. My longer term plan is to design some photo-etch brass but for the moment, I have just painted the original cast mast.
Another long-standing interest is WW2 land wargaming, especially Normandy. I have tried a few different rules over the years without ever quite finding what I was looking for: a battalion-scale game with good balance of simulation and playability. A couple of weeks ago we tried 'Iron Cross' from Great Escape Games.
First impressions were good for playability but less so for accuracy of simulation and (especially) the possibility of scaling up to a full battalion and squadron of tanks. We are playing around with some ideas for house rules to meet these objectives.
Another obvious deficiency from the game was that I don't have enough buildings and those I do have don't look much like Normandy. Thankfully Tiger Terrain have some excellent resin models so I have bought some of those. I was very impressed with the quality and efficiency of their service and the models look fantastic - much the best I have ever seen. If they did models suitable for 16th Century Italy, I could have saved a lot of time and trouble with tiny cardboard rectangles!