At the start of the year I did an evaluation based on product roadmap, production plans, competition, margins, expected free cash flow and various other factors that a fair market price for TSLA was in the $700 - $900 range. With reasonable execution and absent vast improvements by the competition and with no contribution from Tesla network their revenues would grow by 70% and free cash flow by a bit less than 100%. This would continue for several years. So that by the end of the year a fair market price would be $1350 - $1900.
Since then execution has been excellent (not just reasonable), the roadmap still looks good, production plans seem ahead of schedule, competition has been a big disappointment and margins on the Y look very good. So I would now put the end of year TSLA price at $1600 - $2200 and for the end of 2021 as $3200 - $4400. Similarly for 2022, after that I expect Tesla and TSLA to grow more slowly, but still much faster than their peers (Apple, Microsoft, Amazon).
If this evaluation is correct then the current share price is not high and even $2000 is only ahead by a few months, and being at such a price could continue without a significant drop until after Q4 earnings. A share price of $3000 in the next few months would be ahead by a year or so and one of $4000 by 18 months in both cases I would expect a correction back to something around $2000 by the end of the year.
For the share price to reach $4000 or above might happen due to a short squeeze and S&P 500 inclusion, but to stay there would be irrational. However "The market can stay irrational longer than you can stay solvent" applies in this case.
My current thoughts on strategy are to sell 1% of my holdings at $3500 and then another 1% for each $200 raise above that. The on the way down buy back shares. As I plan to buy a house in the next year it doesn't matter too much if I am left holding some cash, my UK capital gains tax allowance would allow selling about $30000 worth of shares tax free, which would be enough for a deposit on the house. That however is second best as I really plan to HODL with most of my shares.