The last decent market wide altcoin rally we've seen was in the second half of 2023 when $BTC started pricing in its spot ETF in January 2024.
Back then, we saw many coins rally as the $OTHERS.D trended up for about half a year.
This is now over a year ago and since then we've not really seen altcoins put in any meaningful moves besides the short post election move. But that one was quickly retraced back down as $BTC stole the show again right after.
Few takeaways:
1. If alts were to show strength at some point, and you do believe there's more strength to it. You want to consider holding the runners for more than just a small move. It can be hard to estimate this but you can generally get an idea of the trend just watching the short term market structure (higher highs/lows).
2. Right now there is still no sign of alts willing to outperform BTC. That does not mean it can't change around at some point. I think it's best to generally wait for strength and then hop on the momentum instead of pre-positioning too early and missing out on gains or underperforming BTC in general.