So you're getting into the piano

Yes. Every method book, every YouTube tutorial, every classical piece is written assuming a full 88-key range. You can technically learn the first three months of piano on 61 keys, but the moment you tackle anything written before 1900 or anything with a real bass line, you run out of keys. Buy the 88-key version. The extra $100-150 is the cheapest upgrade you'll ever skip and regret.

Touch-sensitive means the keyboard plays louder if you press harder, a basic feature on every keyboard since the 90s. Weighted (or 'hammer action') means the keys themselves have physical resistance, the way an acoustic piano does. Only weighted keys train the finger muscles you actually need to play piano. Don't confuse the two; manufacturers exploit the confusion.

For your first 6-12 months, free online resources + a method book are enough for almost everyone. Adult method books (Alfred's, Faber's) are designed for self-teaching. After 6-12 months, a few in-person lessons to fix bad habits (especially hand position and wrist tension) is high-value. Don't pay for lessons in your first month; you don't yet know what you don't know.

Two weeks for a simple right-hand melody, six weeks for two hands together on something basic, three months for a recognizable simplified version of a pop song. The big skill jumps are: reading the staff (week 4), playing both hands independently (month 2-3), playing chords (month 3-4), and putting it all together (month 4-6). Each unlock makes a huge new range of music possible.

Critical. Wrong bench height is the #1 cause of wrist pain in adult beginners. Your forearms should be parallel to the floor when your fingers rest on the keys. If your wrists bend up or down to reach the keys, your tendons are fighting gravity for every note, and you'll develop pain inside two weeks. An adjustable bench is $45 and removes the problem permanently.

Yes; this is one of the biggest reasons to choose digital over acoustic. With headphones plugged in, the speakers cut out and you make zero noise outside your own head. You can practice at 2 AM in an apartment without bothering anyone. Get good closed-back headphones (we recommend the ATH-M40x); cheap earbuds make the piano sound like a toy.

Classical, mostly, for at least the first six months. Method books are notation-based and they use mostly classical and folk repertoire because that material teaches reading and technique most efficiently. After you can read and play simple two-hand pieces, branch into pop / jazz / whatever you actually love; that's also when you'll have the chord-vocabulary to do it well.