Tournaments with rebuys dont require general strategic adjustments. Its all about adjusting to our actual opponents. If someone is shipping to wide, we can look to call a little lighter, but most of the time its fine to just get out of the way and let someone else walk into the line of fire.
R+As however do add another tactical element, which we need to consider, if our goal is profit. This is because, the add-on chips are cheaper than chips purchased before the add-on, and therefore the value of each chip drop, when the add-ons are purchased.
This add a layer of further ICM-pressure during the rebuy period and reward a more conservative playing style. Basically we should try to make it through the rebuy period with as few rebuys as possible even at the cost of arriving with a somewhat smaller stack.
Or we could register in the very last minute, as someone suggested, fold for 1-2 hands, and then purchase the add-on. This is certainly a viable tactic, but we will be giving up on the skill edge, we might have against bad players, who enter the tournament early.
And then of course we should always purchase the add-on. Its fine to not rebuy, if its not a good table, we are tilted from busting, or just dont feel like playing any more. But not purchasing the add-on is literally like giving money away to the other players.
And then as someone else wrote, we need a more solid bankroll for R+As. If we can play a normal 5$ tournament with a 500$ bankroll, then we should only play 2$ add-on events, since we will in reality be spending 4-6$ on each tournament and not just the initial 2$.
With understanding of these additional tactical elements R+As can be some of the most profitable tournaments in
online poker. Some sites even allow rake free rebuys and add-ons, which make them a bargain as well.