You'll be fine

1500 gallons is quite large for 2 people. The general assumptions for sizes tend to just be based on how many bedrooms, and they don't assume you have a high efficiency washer.

You have 2 dry wells. I'm assuming the first flows to the second if the 1st one runs out of capacity, and if the second isn't in use then the system has been well over-sized for the four people. Your washer won't be a problem. [Edited] - the second dry well is a backup should the first fail to function. This ensures that your system is robust.

Regular maintenance is always good for septic systems, don't let it sit for 20 years and there won't be a problem. Pump-outs every 5 years would be more than enough.