tl;dr: The IRS is a bitch and will be looking for ways to squeeze us mooks. Get/keep your trades in order. Report your gains. Report "offshore" holdings in non-US exchanges. Save some gains for Uncle Sam (gotta fuel those air carriers!). If you don't know what to do, seek professional help (especially if you owe from 2017-2018 bull run). All this won't stop you from balding or starting menopause, but it will slow it down and you'll sleep better at night.
Since 2017, I've seen plenty of posts on crypto trading and taxation. I am writing this to bring awareness to anyone who hasn't already taken this seriously.
First off, the IRS is a shitshow, and good luck to them trying to equitably tax the infinitely increasingly complex cryptosphere in the coming decades (they won't). The IRS has clarified since 2017, crypto-crypto trades are taxable events. Prior to 2018, you can make a sound argument that crypto-crypto was like-kind, and those trades were not taxable, simply on the grounds that the IRS did not provide any concrete guidance on the issue until 2018. Crypto-fiat trades have always been considered taxable events.
Now, there are a lot of kiddos like myself who either don't or didn't think about tax implications of trading crypto. Keep your personal records of trades and learn how to report them properly (I invite those of you with more experience with this to post your preferred accounting methods below). There is plenty of literature on how to do this yourself, just do some googling. Keep your records in order, and if you have lost or do not have some records there is wiggle room to fill in the gaps.
Long-term trades (coins held a year or longer) are taxed at 15%. As per /u/Yung-Split's info, if you make under 40k a year long-term gains below 40k income are 0%. As per /u/inethereal's info, if your income is $441,451 or more, crypto trades/gains are taxed at 20%.
Short-term trades (coins held less than a year) will be taxed at your marginal tax rate.
If you've held coins on a non-US exchange, you will need to disclose your "offshore" holdings to the IRS and file some Anti-Money Laundering form (AML), and failure to do so could result in a big wallet-fucking fine (something like $10,000 per offense).
Trades made in the past that you haven't already paid taxes on for that year will accrue late fees and penalties, although there is opportunity to have that kind of thing forgiven if it was pre-2018 since IRS guidance was garbage at best.
DO NOT lie about your holdings, gains, or whatever to the IRS. They will come for you and shake you down. If you lie, this will take you down a never ending path of bullshit that you will have to deal with that just isn't worth it. I'm all for financial revolution, but Uncle Sam owns and operates the playing board, and he wins 99.99% of the time (against normal, non-billionaires).
Don't worry about reporting privacy coins like XMR, there is nothing illegal about having these (yet?). If you've spent small amounts on ahem tomatoes and daisies while visiting the people's market, I personally wouldn't report that and leave it open ended (e.g. you still have that XMR).
My personal experience is that I made big moves in Jan 2018, and owed an assload to Uncle Sam and didn't really think about it until last year. I lost sleep for a couple of weeks before I saddled up and got a professional to deal with all of this for me. In the end, the money spent on peace of mind was worth every penny, I have legal protection, and now Uncle Sam and I are square. Now I can walk around town with my fly down absentmindedly, and have my fiance chide me without worrying that the IRS is going to reach in my pants and yank my dick off.
20 year old me might try and sneak under the radar, but 30 year old me just wants to buy a damn house. Good luck to everyone in this revolutionary endeavor, may Satoshi shine his light upon not only Bitcoin, but all cryptocoins, and may the poor folks around the world be banked, and may Professor Bitcorn roll in his grave. Amen.
