Thanks for the questions.
- Am I obligated to keep my vows when I am on vacation?
I vowed to read a few chapters of the Bible every day. My schedule is very, very overcrowded.
Just to be clear, if you have not taken formal vows with a religious order then you are not bound to them. We all make "promises", which are essentially our good intentions and resolutions to adopt some practice to honor God. These promises are not the same as formal vows given in ordination or other religious consecrations and do not have force of sin connected to them.
That being said, even on vacation it is good to keep up practices that we have committed to on a daily, or regular basic, inasmuch is possible. I find the same challenges. For example, my wife and I do the Bible in a year podcast with Fr. Mike Schmidtz; that gives a great basic reading each day that we can do first thing in the morning (about half an hour). Then, when possible, I will read the same text on my own that evening to frame the day. Also, we always pray the Rosary every day no matter what. So even on vacations we will stick to those basics even if other things get left out. I would suggest you come up with a baseline that you can always do without fail, and make that the "vow", so you never have to second guess whether you are doing enough.
- How should a Christian behave in a sinful world?
There is LGBT and abortion propaganda everywhere. It all irritates me a lot and I often think about that. It bothers me that I can't change anything. Many companies, like Netflix, fund Planned Parenthood and other anti-Christian content.
We share the same "irritation", so you must do your best to be a positive counterweight to the negative darkness that pervades our culture and communities. Truthfulness, sincerity, love, and kindness are the suitable attributes of behavior for any Christian. It isn't easy to be cheerful when so much is depressing so we must turn to the Lord for the grace to be that light.
- Is it a sin then to subscribe to Netflix?
I do not subscribe to Netflix and other controversial providers because they have produced material that not only isn't in accordance with our values, but outright attacks the faith. I see them as serving the interests of Hell, not Heaven. There is a line for each of us and our conscience will help us find it. You may not be able to avoid every company that gives dollars to causes you wouldn't support, but you can certainly avoid those that are positively attacking Christianity directly. Find a line that you are not willing to cross and then stick by it. There is often sacrifice in doing the right thing.
I hope this helps.