So with the recent spike in BTC price (and other ALT coins) when is a good time to sell?

Im particuarly interested in ALT coins as I would be keen to sell these off and invest in BTC or ETH. The ALT coins I have invested in:

TRX
TRON
AAVE
Cardano
Lumen
File Coin
EOS
Polkadot

Also is it worth selling the BTC shares and then rebuying when it dips again?