These doorknobs might be hard to use, if you had arthritic hands, so the idea is to replace them with levers, to make it easier for older people (like us) to open and close them. We started that already with the coat closet, and now we want to continue that replacement on this bedroom door.
First, we purposefully remove the door knob.
And then all it's associated hardware, to get down to just a door, with a hole in the door. Then we put the new hardware on. It takes about 30 minutes.
We are again using Kwikset Tustin Satin Nickel (720 TNL 15) Signature Series. This time it's a "Bath and Bed" model, instead of a "Hall and Closet", so that it can be locked, in need be.
And then a couple days later, we replaced the utility room pantry door knob, again using a "Hall and Closet" model, since we don't need to lock the pantry.
And, finally, after the success of these two doors, we decided to go ahead and change out all the others. We needed 7 more "Bath and Bed" types and 2 more "Closet" types. Instead of buying these at Home Depot, for $29.92 and $25.87 (plus sales tax) for each, I found a place on the web that would sell them for $19.54 and $18.30 each (with no shipping or sales tax). This cuts the cost from over $200 to about $135. We finished switching them all out on 20 March 2015.