The dirty secret is that it mostly works in your favor: Nobody can really force you to work at full motivation and capacity, so most of the time you just cut a mutually beneficial deal when leaving and do it anyway (in a shorter time). The other way around, it means a whopping 6 months of severance.
I've never heard of 6 months for senior development roles in Aus/Uk/Ireland, it is mostly lead, staff or principal roles that have longer notice peroids. It can also be tagged onto a relocation package if they are sponsoring you and/or paying for your relocation.
Non compete agreements, for example, are completely unenforceable. I pointed this out to a former employer who presented me with one. The CEO who was a Business/Law graduate acknowledged the fact and withdrew the requirement to sign.
Only exception for that rules is temporary contract (i.e. for a year). If you have temporary contract, you can't leave without reason. But labor law strictly limits grounds for making contract temporary: basically you have to prove that job itself is temporary (related to concrete project or you filling in for maternity leave etc).
In practice, most permanent jobs with fixed hours have a notice period of 1 month, and 3 months if you're somewhat senior (i.e. not junior rather than very senior). Typically, 3 months is normal until you get very senior, and then you may (rarely) see 6 months, but instead people are normally retained by offering large bonuses that get forfeited on resignation.
If you have a contract that gives you a longer notice period than the statutory minimums (which almost everyone does), then normally the notice period is the same on both sides. If you agree this in your contract, then the longer notice an employee has to give is increased from the 1 week. I suspect this is why almost every company has a contract that specifies 1 or 3 months, because it reduces the company's risk that employees will suddenly disappear and that's more important than the cost of paying someone a bit longer if you've decided to let them go.
But... This usually means that you have a reciprocal notice period if they want to get rid of you.
And... If you decide to not work your notice, you might get sued for the excess cost of hiring your replacement at short notice. TBH, I've seen it threatened but never followed through. You'll burn your bridges with that company / team, but that's about it.
As with many contractual clauses, this is something for you to negotiate over. If everyone in your industry is on a similar notice period, you aren't at a disadvantage. If you think it is excessive, ask to shorten it or for more compensation. Or take the risk.
In practice, if requested, HR will typically agree to shortening it by offsetting accrued vacation time, since it saves money to the company. If separation is contentious, there is also a good chance that the company will just put one on "gardening leave" - i.e. "we'll keep paying you but don't bother coming to the office".
Notice is typically not sued over because a judge might consider it unreasonably vexatious towards the employee, and most people are happy to just take the money and/or free vacation time anyway. Unlike non-competes, it's actually considered in employment legislation.
Although I had a very good relationship with the company and line managers they initially refused my offer to compromise to let me go after 2 months (purely because they wanted an extra month of work out of me). It was only after I made it clear how disinterested I was in working the extra month that we all agreed it was for the best to let me go early. This left a very sour taste in my mouth.
I started as a junior IT Consultant in Hamburg, Germany with a 3 month notice, but could only quit every half year. So for quitting at the end of june I had to give notice in march, and then the next opportunity was september for quitting at the end of december.
But since I'm going back to university now, we made a "Aufhebungsvertrag" so that I quit at the end of september. You have no right to it, but I have a good relation to my employer so they accepted.
EDITED for clarity
I know little about German law, but this sounds insane. I also certainly wouldn't call it 3 months notice, I'd call it 3-9 months notice.
The real question is whether the company could only fire you at these two times of the year as well, or whether it only had to give 3 months notice. If the latter, you might find the courts agree that the contract is unfair if you took it to a tribunal.
Honestly, I think the government need to step in, as a six-month notice period seems like a restriction of liberty to me.
Six month is absolutely not unheard of, although I personally would be reluctant to accept the latter condition. I mean, the clauses are two-way, so they bind your employer as well and protect you from a sudden loss of income, but frankly, I think the benefit to these arrangement are a bit asymmetric.
https://www.eurofound.europa.eu/observatories/emcc/erm/legis...
I have a 'permanent' contract so my employer cannot give me notice without permission from a judge (for example, by insolvency), but the gentleman's agreement is that if they asked me to leave they would continue to employ me until I found another job and provide a small severance (~1 month).
I mentioned it to a recruiter I'm dealing with and she agreed that it would significantly complicate the search.
Not a good sign. Most DE-based eng contracts max at 3 months, or the default per § 622 BGB.
6 months likely means the company fails to retain good staff. Negotiate for asymmetric § 622 BGB notice for yourself, and 3 months notice from the company.
As several others mention here, this is mostly on paper only. In both companies I've seen people leaving with any amount of notice, between 1 and 6 months. You just asked your manager and, if you have decent relationship, you'd get an okay. If you didn't, there's really no reason for them to keep you doing nothing (which, at that point, is almost a given). The only real risk is if you have a really bad manager who wants to "punish" you for leaving, even if this is at detriment of everybody involved.
At least if the company from the OP is a very large one, I wouldn't assume it to be a red flag, but rather bet on the company having an overdeveloped bureaucracy department, who created central contracts who-knows-why and won't change them even though the practice is always different.
The thing about two years is for the statutory minimum notice period, which would be a week for the first 2 years, and a week per complete year worked after that up to a maximum of 12 weeks. However, if you agree to a contract specifying longer a notice period, that takes precedence.
As to other benefits: it's 30 days vacation and they mention profit-sharing, but nothing concrete.