IT is a huge field, so it depends on a number of factors, including your role, how many are also in your kind of role, and the company culture itself.
Some jobs are inherently going to have on-call in some form or another. Developers, systems administrators, and some higher level help desk usually have to be on call at least intermittently, because, let's face it, things don't just break during the 9-5, and sometimes, you have to do a rollout or maintenance in the middle of the night. Such is the life of running critical infrastructure.
However, some jobs don't have on-call at all (or only do as a formality). The manager of a deployment server farm, for example, may not need to have on-call, because the nature of the setup or the business requirements allows a downed server to not be an issue that can't be handled during standard working hours. Likewise, some help desks have strict hours, and business needs that don't require anyone to be on call.
How Many Others Are In Your Role
The more people you have on your team, doing a similar job to yours, the less you have to do the de facto 24/7 on call thing, because there are others with whom to share the load.
If you're the developer and the sysadmin and the help desk, then you're stuck on 24/7 on call. However, if you're one of a team of 10 developers and you have dedicated sysadmins and help desk, then you might have to do a week of on-call once every three months, and unless you happen to get it during a roll-out of some sort, you're not likely to actually be called.
Poor project management and planning from the managers can create overtime where there needn't be any. Some companies even expect people to work more hours as part of their culture (it's not poor planning, but rather a cultural thing; they plan with the extended hours in mind; these are the "burn and churn" type companies).
Conversely, many companies specifically frown upon extra work time and make a point to encourage a typical 9-5, or even fewer work hours.
Likewise, some companies in which on-call is a necessity allow for "comp time" (this is particularly the case for employees that don't get overtime pay). That is, time spent actively working on-call hours (ie - actually fixing an issue) can be taken out of the regular work day. For example, if you spend 3 hours one night fixing an issue, you could come in after lunch, or leave before lunch on another day.
Company Country Of Origin
As part of company culture, where the company originates from heavily influences its view on number of hours employees should work. Traditional American corporations, for example, often expect 40+ out of their people, whereas Dutch companies typically frown upon more than 32-35. Some newer American companies have been implementing such policies as unlimited paid time off, and even minimum required paid time off, so we may see this culture change in the coming decades in the US.
How Do You Find The Company That Matches Your Ideals?
First, write down your ideals. You can't seek out a match until you know what you're looking for -- and for what will drive you away. If you're just getting started, you might have to try a few places out, first.
In the job posting, there are often certain key words that you learn to look out for that are red flags to the type of environment the company fosters. For example, "fast-paced" is often code for "tight deadlines with no or even negative slack" and unless you're a really fast worker, will often result in overtime. "Silicon Valley feel" is usually code for super open floor plans in which there aren't even cube walls between you and your coworkers.
Have a look at their benefits, too. Are the extent of their benefits things you'd typically expect, or superficial things (like ping pong tables)? Or do they mention things like more than 2 weeks paid time off (or, better yet, unlimited, or mandatory minimums), paid maternity/paternity leave (particularly in the US, where it's not required), 20% time, etc? Ask about remote working, too. Even if you choose to work in the office, I've found that their attitude toward remote workers says a fair bit about their culture, overall. If they tout flexible hours, ask about it, too. Is it "flexible" in that you can come in anywhere between 9 and 9:30, or is it flexible in that you can work any time you want, as long as you have a few hours overlapping (or, even better, any time you want, period).
At the interview, ask for a tour of the company (if it's a physical location). Many places are happy to do so. Keep an eye and ear out in the environment in which you'll be working. Look/listen for key things that turn you off or on to the company. (Also, if something like a ping pong or pool table is touted as a perk, see if/when it actually gets used. If you can, ask the people working there that aren't interviewing you.)
Ask how they measure productivity. The mention of 80 tickets in 40 hours vs 40 tickets in 80 hours only applies if the skill requirements of the tickets are the same. A help desk peon might be able to close even 200 tickets in a 40 hour span, while a Tier 3 person may only close 10 tickets in that 40 hour span. Is the T3 less efficient? Not likely. The T1's are probably most password resets, while the T3's are downed servers and hardware failures.