I'm just starting with Google Maps API (GMA for short) and I came to understand it is good to have the GMA Key (GMAK for short) regardless of not being necessary IF you are not to set foot beyond the limit quota. It happens that I probably won't but that is not the concern here.
I just need to note that I'm referring to the v3 version of GMAK. And I have not previously used a GMAK or the GMA; I have always used the code you get from Google Maps itself. So I really don't know much regardless of searching a good amount of time and knowing I will use JavaScript to use the GMA.
I have a lot of websites that I own and some more I administer. But just recently I got the need for GMA for myself and some clients will need too. So here is the question:
Do I need to use a GMAK for each website - meaning creating a Google Account for each website? I mean, is the quota specific to the GMAK or each service will have it's own quota?
And supposing the GMAK quota is specific to website/app and not the GMAK itself: in case of me not being the administrator for one of my ex-clients website anymore, should I inform that I will revoke the GMAK access for that website? Or should I make them provide one GMAK to begin with and not worry it if they finish the contract with me?
I worry and fear that Google will revoke my GMAK because maybe OR all the websites together will reach the quota OR some website of my client will reach it and if they don't pay me, all of my other services will lose the function by not having a GMAK.
The quota belongs to "projects", so you may say it's specific to a key, because each project does have it's own key.
When you can't give a guarantee that access to your key will be granted in the future you should either not use a key or force the client to create an own project and use the key of the client.
However, no matter if you grant access in the future or not, I wouldn't recommend to use your key at all, because when any of the clients will violate the TOS in any manner(there are more cases than hitting the quotas) your own key/project is affected(and of course any webpage/app of any client that uses the particular key). In worst case it may be that your entire google-account is affected.
So you should either use the key of the client(when available) or omit the key.