Vehicle-to-Everything (V2X) is a promising solution to support the energy transition, but concerns about battery degradation and capacity loss remain a major barrier for electric vehicle (EV) users. A clear understanding of degradation caused by V2X is essential to increase user confidence and encourage participation in V2X services. Many V2X studies have researched battery degradation, but the results vary widely between articles, making it hard to draw conclusions. Existing review articles mention the different outcomes but do not discuss the contradictions. In this article, a large set of V2X degradation studies is compared using a quantitative analysis. The yearly added degradation due to V2X is extracted from 37 V2X degradation papers, resulting in a set of 97 data points. The dataset is analysed to compare degradation in different situations and highlight contradictions in similar situations. Results show that the average yearly added degradation is 0.87% (95% CI: 0.35–1.4%). When degradation is explicitly considered in V2X service optimisation, the added degradation is limited to just 0.9% per year. Moreover, under specific conditions, V2X can even help reduce overall battery degradation by reducing calendar ageing. Temperature and SoC are especially important in assessing the benefit of V2X on calendar ageing, but these factors are most often overlooked. This review has highlighted common shortcomings in V2X degradation literature that affect the assessment of the impact of degradation. The results can be used to clear up misconceptions about degradation in V2X and to guide future research directions.