Penny stocks is the school of hard knocks
Yes it is! I learned this the hard way as I watched a $4k profit shrink to less than $1K in a single day because I didn't take any profits after the penny stock spiked (and then dropped).
That's a good strategy is to take the majority of your gains off the table and then leave a little bit in case you really do find a unicorn of a trade (10-100 baggers).