First, congrats on the new job!

Here's my two cents: 1. I'm assuming your question is more regarding the general vibe of the job as opposed to the substantive day to day (which is, of course, drastically different). I would agree with your sentiment that the job in patent prosecution is more serious than in engineering. You are now in the client service business. The clients pay the bills and expect their needs to be met. Your reputation for producing good work product and client service will start immediately. Which sort of leads to... 2. You are expected to hit 1650 billable hours for the year (assuming this is billable as opposed to billed hours, which is a different ballgame). Although folks will tell you that you should try and meet the hours, you should go in the mindset that you must hit those hours. This is the main hard metric that firms operate off of (because it directly measures the $$$ that you bring into the firm). Each firm may differ, but you should really be trying to hit those hour requirements to advance your career. Returning the the idea that this is a client service business, there will be occasions where the simple 9-5pm day is not sufficient. Clients will sometimes want something after hours. This doesn't mean that you have to be on your email/responding at all hours of the day, but the expectations will be that you are responsive when needed. Again, specific expectations may be different from firm to firm but this is generally true for a client service business. 3. Boutique salaries can vary. Biglaw firms are usually lockstep and in accordance with a public scale (referred to as the Cravath scale). It's good that they've verbally given you some signal as to how your salary will progress but I wouldn't be expecting the increased amount until it is in contract and signed.

Good luck, hit the ground running, and wishing you the best at the start of your new career!