Shoe lasts are not designed for toe length. Designers can and do not account for every length of toes with regard to a shoe form. Lasts are designed for arch/instep, ball and heel. Some feet just do not fit in certain lasts no matter the shoe design or size. That is why your shoe salesperson will tell you to fit the larger foot. However, many choose to wear an ill fitting shoe strictly for fashion. Many also end up ruining their feet for fashion or from wearing the wrong size or an ill fitting shoe.
In the case of slides and sandals, width and comfort determine mostly if a shoe fits. Toes and bony part of heel are aesthetic choices and not fit issues.
@tulipfield, I cannot imagine that the next size up would fit you well. I expect that would slide out as you walk.
As a shoe sales person in a former life, I saw very few feet with Orans that were too small in this thread. I saw several that were too big. It is completely ok (and often preferred) for toes and the bony part of the sole to go to the end of a slide/sandal. A sandal is not a closed shoe, so many fit rules do not apply similarly. As pp said you don’t wish for any toes to drag on floor or be pinched. You also don’t want any bony sole to hang of the back of shoe, or the heel will tire quickly when walking. Too much leather showing in the front or back will lead to unnecessary leather wear and often be a safety issue as you walk.
