You’ve gotten 2 excellent answers so far. Can’t add too much, except for personal experience (builder for over 20 years). When my brother and I tackled a similar issue, we eventually got the job done, however, there was a certain amount of “BS’ing” and beer drinking that went along with the work that wouldn’t have happened had this been a “regular” remodel job.

The Length of time would depend upon whether it is pre built or whether the units need assembling themselves. But assuming that they are pre built and assuming your boyfriend isn’t a kitchen fitter… I’d say 1 - 2 weeks is reasonable. You have to remember on shows on TV their are teams of 20 experienced kitchen fitters all working on one kitchen! Which makes assembly possible in under a day. But go easy on you man at least he is fitting the kitchen!

I have kitchen remodels take 3 weeks and some that took 3 months (like my own) and I even had one that took 1/2 a year. A lot depends on, what needs to be done and who is doing it. I’ve designed kitchens where the client wants to do just the demolition and tradespeople come in to do the rest. And, I’ve had remodels where I only did the design and the homeowners do everything. In my experience, the latter take the longest of all. Most of the time homeowner’s get in a little over their head and take longer to do just about everything than the tradesmen do.

Bless his heart, but my own hubby has found sometimes a simple appliance installation requires much more time and effort than he originally thought. (like our convection oven wouldn’t fit in the hole in the cabinet, so that had to be reconfigured before he could install it). Sometimes, the electrical needs to be changed, ductwork isn’t located in the right place for the new appliance, origianl plumbing in older houses wasn’t designed to accomodate disposals and dishwashers…The problems one encounters can be countless and overwhelming. On TV, you don’t have the project shown to you in “real” time, you don’t generally see the problems and there are always experts behind the scenes as consultants to move the project along.

Be kind, be sympathetic and most of all be patient.