I came across these interesting articles regarding "CLA vs overhaul".
Reading many forum posts and classified ads it seems that many times these words are used interchangeably when there is obviously a significant difference. Reading these articles, the implication is that that a CLA is a waste of time and money on a 50+ year old mechanical camera such as a Leica. It in fact does more harm than good according to the writer Henry Scherer. A complete overhaul is always necessary and you can't do that in a few days for a couple hundred dollars or less.
" So here's the long and short of it. CLA usually means that you have been robbed and your camera has been set up for a very expensive repair. I have yet to see a camera that has supposedly had a CLA which has actually been cleaned and lubricated. All have been dirty and full of old hardened grease, dirt and metal wear products. Some have been "adjusted", and adjusted is not the right word because it does not mean "full of bent parts".
"The main problem I see with cameras that are sent to me that are not performing properly after having had a CLA is that when I open the camera it is apparent that absolutely nothing of any substance has been done to the camera. I have yet to open a camera that has had a CLA that is not filthy dirty inside with the parts either not lubricated or covered with ancient hardened lubricant. In some cases I have seen cameras that have been lubricated, but the lubricant was uselessly applied on top of parts instead of underneath them where it should have been applied"
"If you do send your camera to someone for a CLA, and you are fortunate enough to really get one you should understand what a CLA really is. If it is an "honest" CLA, and I've never yet seen one of these, it is a very superficial camera service that is appropriate only for a camera that is in otherwise full functioning condition and which has been regularly receiving "honest" CLA's on a frequency of no less than 5 years throughout its life. In the old days when people could afford to purchase mechanical watches everyone knew it was necessary to have the watch cleaned, lubricated and adjusted every three to five years. This wisdom was also well known among camera owners because of the similarity between watches and mechanical cameras. But this knowledge is not so wide spread today"
Well if nothing else, Mr. Scherer certainly doesn't mince his words. While he seems to be specifically talking about Contax cameras, from his perspective it probably includes Leicas as well What are your thoughts on the subject?