It depends. Sometimes prices will be stable and sometimes prices go up and down a few times per day. For your dates, Villas Jibacoa was available for $447. (all in) a few weeks ago and now it’s $589. Prices change based on how the seats on the plane are filling up -that simple. The plane is the controlling factor in most cases.
If we have warm weather in Toronto, less people buy, prices go down. More snow, prices go up. BUT … big but, if too few people buy, then they consolidate planes, so your Veradero flight may stop at Cayo Coco, etc. If that happens, there are now fewer seats so prices will not drop. You also are inconvenienced with an extra stop.
Does it sound like the stock market? - yup! Supply and demand. Hotels, resorts, etc. all do the same thing. My daughter used to be in charge of the front desk at a hotel. If they thought they would be full, they charged ‘rack rate’ (full price). It’s illegal to charge more but they would if they could. If they are empty, they’ll drop the price to bargoons - 75% off.
Last year, I watched multiple resorts 3 times per day and saw a steal come up mid-morning. I pulled the trigger and booked 6 people at a 4 1/2 star @ $600. As I was on the phone, the price went up over $200. I got the lower rate but it continued to rise to well over $900. It did not go down. Regular prices are over a thou for that resort. Sometimes, you can get a bargain one or two days prior but these are getting more rare.
To answer your question, my advice (and most on here would agree) if you have a set resort and dates that are not flexible, book as early as possible. If you can move your dates and/or willing to try other comparable resorts, then keep your eye on prices for one month prior and book when you feel most comfortable. Once booked, do not look again. 50/50 odds you’ll get upset.
The real tried and true gamblers who want the ‘best bang for the buck’ book in the last 7 days but are willing to go somewhere new and willing to stay home if the prices are too high.
BTW, if I could save $500. for 2 people by flying out 3 hours early, I’d go early. Geez, that $133. per hour tax free savings and you still have a question??? Of course, if you are that wealthy, why not try Cayman Islands, much nicer than Cuba. : : :