Our construction started at the end of April 2014. We moved in in November 2014. Our kitchen search (first meeting) took place in May 2015. Then the negotiations began with two studios in parallel. In the end, we placed the order in mid-July 2014.
The kitchens from the offers usually do not fit your individually designed kitchen (dimensions) anyway. Therefore, you can rarely use the "super-duper bargains." Furthermore, you usually have to make compromises with "bargain kitchens" (swing doors instead of lift-up cabinets, position of cabinets, color of corpus, countertop, etc.). Aside from the fact that with these bargains from the kitchen studio there is always some saving somewhere (e.g., cuts in the electrical appliances, or similar). In the end, you will put together an "individual" kitchen. After all, you want YOUR kitchen with YOUR realized wishes in YOUR house (as far as affordable). You can have this made for yourself at any time independent of the bargains.
Last but not least: Without knowing your wife - she will very quickly push every bargain kitchen toward the "throw-away pile" because she has her own idea of her kitchen. And if she threatens: "If we don’t take this countertop, I won’t cook in the kitchen," you have already lost. OK, actually I didn’t really care because I cook myself 75% of the time anyway - but I didn’t want to risk the other 25% as well as the household peace.
I see little point in starting a year in advance. A few months before is sufficient so you have peace while planning and the kitchen manufacturer has enough time for production and delivery.