The performance of the HST model is amazing (30-50% per year on average), but it shows significant drawdowns (-35/50% in some cases).
In bad times of the markets investors could panic and get out of the model, hurting themselves: seeing our capital cut in half would destroy the believes of many.

Another way to reduce volatility and risk: I have to choose a trading strategy which is more adequate to my risk profile.

Here's how to manage this very important issue

The HST model gives signals. Using with signals, investors shift among 3 positions

1. Aggressive Long
2. Moderate Long
3. Cash/Short

 The original version of the model (actual variant 2) suggests the investors to go

1. 100% $TQQQ
2. 100% $UPRO
3. 100% Cash

but we can apply less risky ETFs (with less or no leverage) and reduce drawdowns consequently.
In some cases, we can apply an inverse ETF (like $QLD) instead of going Cash to take advantage of the bear markets too.

These options  build up a set of strategies, each suitable for different risk profiles.
(variant 1 is the most risky/volatile, variant 5 the less risky/volatile)

[Note: when we choose to apply the HST model with leveraged ETFs, we apply it only for a part of our invested capital: this is money we do not need for our regular life. We are making a risky bet to see our capital grow, but you never go all-in with that bet, just invest a small part of capital]