I seriously doubt it is a matter of luck at all, so you need not worry about it.So far, my last two labbies from DL have been <1% stability. Let's hope this good luck keeps up -Alex
It is a matter of what CNI is currently 2015 able to make and deliver on purpose as a matter of business, not a matter of luck.
It is a matter of business practices and what CNI is capable of making at low or at least reasonable cost these days and wants to deliver for whole variety of reasons --technical ability, quaity control ability, ability to mass produce, economic/financial considerations, being competitive real world of 2015 laser marketplace, laser application needs of customers, marketing/creating demand for product, and many others.
There are a lot other laser makers that offer for example DPSS 532nm lasers with stability of <1%, < 0.5%, even < 0,025% and beyond as standard off the shelf items in 2015.
"Lasers—once an inside secret (or more tritely, a solution looking for a problem)—literally surround us in our everyday lives and are finally being recognized globally and politically: first through the 50th Anniversary of the Laser events in 2010 and now through numerous global initiatives such as the United-Nations-decreed International Year of Light and Light-Based Technologies (IYL) in 2015" From: Laser Marketplace 2015: Lasers surround us in the Year of Light - Laser Focus World Nice chart in the article also, showing forecast of 2015 global laser revenues. $9.75 Billion, divided 55% non-diode and 45% diode--serious business these days, not just pretty words.
In your application --"viewing the beam" you don't really much need to be concerned % stability rms over 4 hours. Without a laser power meter, your eyes wouldn't see/notice a 5% or even 10% drift away from 176.2mW in output power over 4 hours .
Where % stability rms over 4 hours might be a factor is if and when you decide to sell it as a used laser---a modern/current technology laser with very good stability could be a selling point depending upon the intended use requirements
Interesting article on state of the art laser stability as of 2012 - have a look -"the world's most stable laser – with frequency variation of no more than 2 parts in 10,000 trillion" From: The World's Most Stable Laser