One of the primary factors I often consider when working with the snakes in my care is security - what helps them to feel safe and comfortable in their environment, and what tangible assurances I can provide to facilitate that for them. Security feels like an especially imperative consideration with sensitive species, such as the Spilotes sulphureus which I work with. Being large, intelligent, active, and vigilant snakes, they require a higher threshold of baseline security than I expect from slower moving colubrid species, such as kingsnakes. Such heightened assurance can be challenging to provide in captivity, as the primary way of achieving security that Spilotes tend to utilize - flight - is not as available to them as it would be in their natural environments. They simply can't speed away and disappear into the jungle, because they are confined in the smaller spaces of their enclosures. In my mind, this places a greater imperative on a few other factors that influence security, namely enclosure size, diversity of hides, and baseline foot traffic within the vicinity of the enclosure.
In terms of enclosure size, larger is nearly always better for Spilotes in my experience, except perhaps in the case of acclimating freshly imported, field-collected specimens (which I will discuss in greater detail below). Many keepers attest that depth is a particularly critical dimension, as it can facilitate the animal maintaining a certain flight distance - the distance that describes the threshold at which an animal feels the need to move away to maintain its sense of security. For arboreal species, height can offer a similar assurance, and I have found that allowing the snakes in my care to move to heights above my head will often help them to feel safer. This pattern reminds me of birds, which will often perform a 'hook' by rapidly ascending to a branch just out of reach while a terrestrial threat moves by, then simply return to their original location after the threat has passed. By allowing snakes to access greater heights by either utilizing tall enclosures, or by elevating shorter enclosures by placing them on a shelf or stand, the keeper can help the animal to self regulate its sense of security.
Offering a diversity of hides within the enclosure is another way that the keeper can increase security for the snakes within their care. For the sulphureus under my care, the preferred hides I use are large cork rounds, which can be easily mounted in the branches at varying elevations, serving a further purpose of creating basking platforms, while also offering a naturalistic aesthetic appeal. Truthfully, any number of hides could be considered appropriate - from cardboard or wooden boxes, to commercially available plastic options. What is most important is to provide a diversity of options, particularly across a varying thermal gradient. In vertically oriented arboreal enclosures, such thermal gradients are typically achieved by mounting a heat source on the ceiling of the enclosure, creating a warmer upper area and a cooler ground temperature. By placing hides at varying elevations across this thermal gradient, the keeper can help the snake to self regulate it's body temperature without sacrificing security. I observe the sulphureus in my care to utilize arboreal hides almost exclusively, in favor of terrestrial options.
Another factor I typically consider in evaluating security for the snakes in my care is baseline foot traffic within the vicinity of the enclosure. Spilotes are very vigilant snakes which tend to keep a close eye on their keepers or anyone within view of their environment, and it is often a tenuous trust at best that exists between such snakes and passers-by. Sometimes this can translate to significant stress for particularly sensitive specimens. To address this, I utilize enclosures which have a transparent glass front and are otherwise opaque, which helps to limit the amount of visual stimulus the snakes receive from people moving through the rooms where the enclosures are situated. For snakes newly adjusting to display enclosures in places with moderate-to-high foot traffic, it can also help to temporarily place a blanket over the front glass panel to further reduce stimulus, which supports the snakes to gradually adjust, establish security, and become familiar with their new environment. This is often unnecessary if the enclosures are situated in areas that don't receive much foot traffic, but is a helpful option to consider in some circumstances.
Sensory overwhelm is a serious concern for some Spilotes, and it's often a grave problem with freshly imported, field-collected specimens which have yet to establish themselves in captivity. In such cases, I have found that limiting sensory stimuli, particularly visual stimuli, can benefit some snakes in the short term, until they are well-established, feeding, and treated for parasites. To achieve this, I use opaque plastic storage totes as acclimation enclosures because they create a secure, insulated environment which is also easy to clean and durable. That said, I don't see such enclosures as ideal long-term housing for snakes, as I severely doubt sensory deprivation can create a healthier environment for any animal in the long term. In short, sensory deprivation is merely one of many tools that can be used in select circumstances to enhance security, and even then only in moderation, from my perspective.
In summary, I view security to be one the most critical factors to consider in evaluating the effectiveness of any snake keeper's care strategies. Captive snakes that are deprived of adequate security invariably live under very high levels of baseline stress, failing to thrive and often exhibiting highly defensive behaviors which only exacerbate things for both keeper and kept. Alternatively, when snakes feel secure in their environments, they're much more likely to express natural behaviors, and they're often much more tractable and curious in the hands of their stewards, making the rewards even sweeter.