Daedalus and Yoroi were made by IOHK and Emurgo (indirectly), so the credibility is there right from the start, and we can trust it (that it is not meant for malicious intent).
But when it comes to wallets that are made by the community, how do I know that it is safe to use? What are the parameters we should check first, to make us certain that our private key or seed phrase is not being collected by the wallet platform?
DO YOUR OWN RESEARCH!!!
Not to sound pretentious or unhelpful, but lets imagine a spectrum of trust:
On one end, there is the super paranoid computer nerd who doesn't use any software unless they can read and audit the code themselves. On the other end, there is the naive grandma who downloads/executes anything the screen tells her to. Where the rational person falls on this spectrum should vary GREATLY on a case-by-case basis.
For example, your criteria for trusting a proprietary social media platform with your personal info will (hopefully) be very different from your criteria for trusting an open financial platform with your assets. Ask yourself: "If I trust software developed by IOHK, how did I come to such a conclusion, and how can I use the same process to come to conclusions for other open source products?".
Software reliability should not be thought of in absolute terms. The amount of trust you place in any kind of software product is a personal choice that YOU must make in accordance with your individual circumstances and what YOU believe is appropriate. Ask yourself:
As a personal example, I have very little coding experience, but from hours of community engagement here and on other forums, something like Nami Wallet SEEMS like it is trustworthy. The creator has a solid track record of community engagement, it is recommended by many community members on several different forums/info-sources, and nowhere have I seen anything catastrophically negative said about it (I can say the same for several other SPO tools such as CNCLI and the Guild Operators suite). Would I store millions of dollars of assets on it? No, but nor would I store all of my assets on any one single wallet, even one developed by IOHK.
To summarize:
One must figure out an appropriate "amount of trust", per "unit-of-value", to place in a product of a "perceived-reliability".
Sorry if this response is long-winded or over-generalized, but I believe that everyone in the this community is pioneering the shift towards a world of true data sovereignty. It is therefore imperative that we develop the necessary skills and habits to thrive in such a world, because with great power comes great responsibility... just my two cents.
So say it with me:
DO YOUR OWN RESEARCH!!!
:)
