If you have small children, double any estimate from anyone who doesn't have them

....
Just to give you a comparison from another partly DIY project...
We've planned virtually everything ourselves, even opening the drywall to find vent paths etc. We have an awkwardly shaped space so the planning and figuring was a big deal. We are doing all cabinets and counters (wood) ourselves; hiring minor plumbing, electrical, & venting (but we've pitched in on occasion so they don't need a second hired guy for the grunt work). Floors & walls were completed prior to our arrival on the scene & plumbing was fixed. We have 9 full depth base cabinets (including one 37" corner), 3 shallow depth base cabinets, and only a couple of wall units. We will have a slide in downdraft range on a pennisula, which has necessitated a fair amount of figuring and requires some tight coordination of our efforts with those of the electrician and venting guys. We've been working on weekends for several months now and we've built all but two cabinets, leveled, mounted, and ganged together several key sections, cut & finished the sink counter, cut & mostly finished the wall counter. We've also built some closet shelves, purchased appliances, etc.. We still need to cut, tie together, & finish the sections for our penninsula counter, attach all counters to the cabinets, assemble most drawers, put on doors, add handles, & tile the backsplash. In coordination with venting and plumbing and electrical! We're hoping to be done this month but it may be another week or so.
But...we have a daughter who demands a fair amount of attention and we don't currently live where we're installing the new kitchen, so we have to get our collective acts together everytime in order to get out & do something! Assembling the cabinets really is easy once you get used to it. We've generally finished a few each time we go, plus odds and ends of other projects, humoring the kid, etc.. I'm sure we could have done all of the assembly in a marathon weekend if we were on site and had childcare. (And if we were more efficient about our Ikea visits... seems like we're there a couple of times a week!

)
So far we've found the slowest part (not hard, just slow), is leveling cabinets and figuring out just *exactly* where to cut the counters for sink & stove. Finishing the wooden counters also demands time: not much for each coat, but every day you need to go back and do the next one. I'm expecting tile to be a bit of a challenge: my husband authorized outlets within the planned backsplash zone and now we're stuck with them unless we pay more but they can't be finished until we tile. Having never tiled before I didn't really need that kind of time pressure

...oh well.
So I guess my timeline for actually working on something is about 3 months under restrictive conditions. Some of the planning happened in the several months prior to that and some of it has happened mid-project (when you realize your downdraft vent might wind up inside a wall you need to take a break and figure it out

. I'm guessing you can do much better!
Hope this helps a bit,
NB