If the toy uses Ni-Mh cells then always make sure to run it right down and then fully charge it each time. Ni-Mh and Ni-Cd have a memory effect where if you don't charge for the full length of time it can shorten the charge it will hold over time. I killed a few power tool battery packs before learning this.
Li-ion cells don't suffer from this problem and are much more forgiving, but the products that use Li-Ion tech are more expensive to buy.
We recently had a Fun Factory Bi Stronic Fusion due on us after not a huge amount of use. LH were understandably not able to do anything as it was out if warranty. However, on contacting Fun Facitiry customer service in Germany we found that they have a 2 year warranty on their products. A replacement is currently on its way to us. Impressive 👍