The amount of work involved in a Kit is as varied as the cost. The early Europa aircraft were taking 1500 to 2500 hours to build, which as FFF says, is too much if you do not enjoy the process. On the other hand some of the micro 3 axis aircraft such as the C42 can be put together very quickly and are really just an assembly job. C42’s are generally flying in less than a year from purchase.
I am at the beginning of building an MCR01, which I expect to take 2.5 to 3 years to build. Total cost will be 40,000 to 45,000 but the running costs will be much less than my AA5B. I hope to keep it for a long time!