Should you take all your allocated PTO at "FAANG" companies or will that affect you when it comes to performance reviews or promotions?
If you work in a good organization, you should take all the PTO you need to function as a regular human being.
Something I loved about working at Meta (which is full of great engineering organizations) was that it was all about impact:
I saw several engineers in both buckets during my time at Meta.
I think this confuses a lot of engineers coming from less-rigorous companies than FAANG as the perception of work is often more important than the actual output at these places (I have worked at companies like this too). People who work massive hours to middling impact are perceived as "hard working" when they should be labeled as what they truly are: Inefficient with poor work-life balance who also need to learn how to work smarter.
I was actually more in bucket #2 at Meta. Through many trials by fire across 3+ years, I was able to function as a high performing tech lead working more 35 hour weeks than 45+ hour ones. Here's a bunch of resources to learn how I did that:
Lastly, I really want to call out how much of a myth it is in tech that when you trade in extreme amounts of time, you unlock more productivity. This is simply not true. If you're working late hours and sacrificing PTO, you're going to become depressed and constantly riddled with brain fog. This is going to make you:
"Work hard, play hard" is sort of a cliche, but it's directionally correct. Live your life so that your mind and body are in a good state to do truly amazing work.
Be strategic about when you take PTO. If you're planning to take extended time off (2+ weeks) then you should mention it well in advance and do it when there are no critical junctures for your project.
I don't think about vacation as "how much of the PTO allocation you're taking?", but more of "how disruptive is your vacation for your teammates?"
Take your vacations. Companies that offer countable PTO like most of the FAANG companies expects employees to take them, and HR will nudge managers to tell their reports to take days off when it starts piling up (from what I understand, it's because PTO days are sort of a liability for the company).
Your manager and your organization should be accounting for all the PTOs and leaves you end up taking in your performance evaluation. In theory, the impact/contribution etc should be prorated for the time you actually are doing the work. For example, if you were on a 3 month parental leave this year, they should be evaluating your performance given you had only 9 months to complete the work instead of the normal 12. So no, in no circumstances should your performance evaluations be impacted by PTO (except situations where you abuse the policy, e.g. taking waaaay too many sick leave even though you weren't sick).
Rahul is right though about the fact that you should try to minimize the impact of your PTO on your team and project. Your longer PTO will probably impact some project timelines, but it is really up to your manager and leads to decide whether that's actually problematic and they need cover and adjust timelines accordingly. Most good organizations do this already and adjust timelines for times of year where many people take PTO, such as Q4 in the US or the summer in parts of Europe.
A good rule of thumb is to give the equivalent times amount of notice period for your team and double for your manager for long blocks of PTO so they can plan around it if needed. E.g. taking 2 weeks off? Notify your manager 4 weeks ahead and the rest of your team about 2 weeks ahead of time.
Lastly, for longer PTO blocks more than a few weeks, employ good practices like setting auto-reply for your email/chat app ("I'm out from x to y, contact zy@ if you need help") and potentially create handoff docs for your team in case they need to take over for you.