Jenna: I think your basic feelings on this point are correct. It is absolutely true that any agent worth his/her salt will make sure you are contacted as quickly as possible if there is something in the offing that concerns you, because, of course, they need you to make the audition in order for them to secure a return. They are never going to leave you in the dark if there is something on offer.
But, equally, if there isn't, there is not really time in the day to be worrying about contacting any clients who are *not* being offered work just at the moment apropos of nothing whatsoever. So agents get in contact when they need to.
How often the actor should contact the agent is a different question. I think this rather depends on the relationship between actor and agency - some are based on a much more personalised and one-to-one relationship between agent and client, and some setups (particularly the larger ones) are rather faceless, which does alter the ease with which this sort of rapport can be struck. Generally, though, it is most useful, in my opinion, to contact the agent when there is something of significance to be mentioned to them. Again, what you can 'get away' with revealing is dependent on the attitude that your agency/agent holds towards you, but, amongst other things, I speak to my agent to tell him about any problems with availability I may have in a coming work period, to alert him to any work I have done (with his blessing) independent of work he has secured me which he might be interested in seeing/promoting/showing to interested employers, to keep him up to date on things like new headshots and showreel development, to mention any castings that I have seen that I think suit me in order to doublecheck that these breakdowns have been addressed by the office, and so on. This all sounds very businesslike, but it all allows very powerful incentives to talk directly to an agent about issues that are arising and affecting your career, to demonstrate your professionalism, to remind your agent of your commitment to their work, and to help them (hopefully) promote you more effectively. The agent may not have masses of time to deal with this, but they will not consider that the time is wasted discussing such things either.
On the other hand, I tend to discuss this most effectively with my agent via email, rather than directly on the phone - tending to phone the office only when something has arisen directly in response to the agent's phoning me previously. Luckily, my agent is very email responsive, even to the extent of being happy to cut and paste from his database of Spotlight applications made on my behalf in, say, the past month, and sending me an attachment so I can review these for myself. Not all agents/agency are, perhaps, so accomodating. But email is often preferable - for the simple reason that an agent can deal with it on his/her terms, as and when they need to, rather than feeling pressured to deal with enquiries or details as and NOW, which tends to be the result with phone calls. Some clients have agreements with their agents that they put aside applications for, say, the first hour of the working day, and this is the time for the client to ring the agent if they wish to touch base with them. All of these kinds of arrangements can be useful for reassuring the actor that the agent is working hard on their behalf and, if work is drying up, it's not for want of trying - and they tend to be based on personalised agreements. It is worth canvassing your agent/agency on what their attitudes towards these kinds of setups are if you don't already know it, because they may be more prepared to 'keep you in the loop' than you realise - provided that you play in accordance with a set of rules they are allowed to specify. Often, this should be something you should try and establish with the agency before you even sign with them - most agents know whether they are prepared to field calls, emails etc. etc. long before they agree to take you on.
As to ringing *every* day for the Spotlight applications - I imagine that it could work for some actors if the agents are prepared to reel off these details, and if it helps them to keep in touch with their agent - but it strikes me as excessive, not least because knowing these details is hardly relevant in itself - anything that secures an audition you are bound to get alerted to, anyway. The benefits of it are: to remind the agent of your commitment to the agency, and to get feedback on how hard the agent is working for you. Still and all, I don't think every actor is put up for something every single day of the year, and I also think it is just as simple to get this kind of information at intervals - for example, I can obtain lists of Spotlight applications made on my behalf with dates of application appended when I ask for it, and I ask for it sporadically, say after a month or two has gone by since I've seen the last one. That seems more than adequate to me.
One final point is that, if you are afraid to *ever* ring up the agency office, for fear of being bawled out, or are actually at risk of being criticised over the phone for having had the *audacity* to ring, you are undoubtedly with the wrong agent. Most agents won't have much to say to you if you are ringing for no good reason, and, even if you have a good reason, they may be so harried that they will listen briefly, take down what you've said, and then promise to be in touch soon (i.e. give you short shrift), but you should not be in a situation where your own agent doesn't even want to give you the time of day - that's just wrong.