Kitchen remodeling design, fixtures and installation

[Philip L.]

Just about to start a complete renovation of a rental property I purchased this week, one of the things the property needs is a new kitchen.

This is the first time replacing a kitchen so I have a few questions and hoped you guys could give me some top tips.

My plan is to buy all the cabinets, counter tops, materials and appliances a mixture of new and used then have a contractor install/fit the entire kitchen.

Questions
is there a decent kitchen design software anyone can recommend that can help me design the layout with measurements and visuals?  
 
On the second hand market I've seen a good number of complete kitchen cabinets that have been removed from renovations, they seem to save money but considering how precise everything needs to be in a kitchen are they worth considering or am I best off just buying new? 

Anyone with experience of installing a new kitchen for a rental property offering any advice or tips that would be appreciated thank you